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Vaccination

By Radaporn Chutanopmanee, Sirayawadee Maneesilp, Nonthasorn Wongsirilert, Thanrada Vittayapanyanon, Pattaravit Kumplean, Jesnaronk Jesadanont, Panisara Aursak, Pimlada Klaingjun, Natnapin Chalermpongpakorn, Jibhassorn Laoluechai, Napasjutha Kongsonthana, Onnicha Siriudomsait, Jinnipa Banditmahakun, Pathariya Pensiri, Phakchira Naranunn

Edited by Thorphan Tienboon


WHAT ARE VACCINES?


Last century, vaccines are one of the outstanding public health achievements. Each year, approximately 2–3 million lives are saved by vaccinations. A vaccine is made from weak or dead germs that represent diseases in appropriate amounts such as viruses, bacteria, and toxins. Vaccination is a secure and competent method to prepare your body and lessen the risks of getting a disease by causing the immune response produced in the body.


Your immune system responds to the vaccines by the following steps:

  • Recognize the invading germ, such as the virus or bacteria.

  • Produce antibodies which are proteins produced naturally by the immune system to defend against disease. Each pathogen in the vaccine contains antigens that induce cell-mediated immunity by activating highly specific subsets of T lymphocytes.

  • B lymphocytes synthesize specific antibodies to remember the disease and how to suppress it. If the remembered antigens are detected in the future, your immune system can destroy them early.


This immunological memory – the foundation of long-term protection and the goal of vaccination – is characterized by the durability of antibodies and the rapid regeneration of memory cells that can be reactivated after exposure to the same pathogen. The protection of a vaccine (even taken once or more doses) will last for a year or even a lifetime. This makes vaccines so efficacious by preventing disease before it occurs.



Types of vaccines


Inactivated vaccines

Triggered pathogen-based vaccines are made by inactivating all pathogenic preparations by heat, radiation, or chemicals such as formalin or formaldehyde. Deactivating disrupts the capability of pathogens to reproduce and bring on the disease. Moreover, they also allow immunization, with the purpose that the immune system can memorize the aimed pathogen. Inactivation methods were used for earlier vaccines such as typhoid fever, plague, and cholera. IPV, whole-cell pertussis, rabies, and hepatitis A vaccines are currently inactivated vaccines.


Live-attenuated vaccines

Live vaccines are produced by a weakened or attenuated germ that causes disease such as Measles, mumps, rubella (MMR combined vaccine), Rotavirus, Smallpox, Chickenpox, and Yellow fever. These vaccines are similar to natural infection, so the immunity can be long-lasting. Live attenuated vaccines are normally made by viruses more than bacteria since viruses have fewer genes, and they can gain and control attenuation more reliably. The most ordinary way to get live vaccines is to transmit the virus through in vitro cell culture (eg, in chick embryo cells). In each way, the selected viruses infect and replicate better in cell culture, but gradually lose their efficacy to infect and duplicate in their original human host. This method selects viruses that reproduce well in low temperatures, not at body temperature, thus the vaccines can help reduce the incidence of disease in humans. These vaccines must be kept at a cold temperature to remain the viruses.


Messenger RNA (mRNA) vaccines

mRNA is a step between the translation of encoding protein in DNA and the protein production process. Nowadays, two main types of RNA are being explored as vaccines, unreplicated mRNA and self-expanding viral-derived RNA. They do not just encode the antigen, but also include a virus replication mechanism that allows for intracellular RNA amplification and expression of many proteins. This property could be functional for vaccination. In some cases, mRNA may provide complementary activities to drive dendritic (DC) cell growth and thus induce strong T and B cell immune responses. However, innate immune recognition of mRNA is also associated with inhibition antigen expression. Therefore, it may affect immune responses negatively. mRNA vaccine produces proteins to trigger the immune response. Compared to other vaccine types, these vaccines have many pros due to shorter production times and no causing-disease risk for vaccinated people, for example, the COVID-19 vaccine.


Recombinant vaccines

The efficacy of recombinant vector vaccines is proven to prevent infectious diseases in animals, including rabies and distemper. Most of the vaccines are developed by NIAID researchers in the 1980s that use weakened poxvirus to deliver the pathogen’s genetic material. Today, NIAID-supported scientists are developing and evaluating recombinant vectored vaccines to protect humans. To be specific, the recombinant vector vaccine uses a live attenuated microbe (such as a bacterium, virus, or parasite) as the vaccine vector to express a heterologous antigen(s). The first experimentally verified recombinant vector vaccine is a Vaccinia virus recombinant that expresses hepatitis B surface protein (HBsAg), which was shown to stimulate the host chimpanzees to induce immunity sufficient to protect them against virulent hepatitis B viral infections from viruses such as HIV, Zika virus and Ebola virus.


Subunit vaccines

Subunit vaccines, similar to inactivated whole-cell vaccines, contain only non-living parts of the pathogen. Still, they only consist of the antigenic parts which are necessary to activate a protective immune response, making them differ from inactivated whole-vaccines.

However, there might be some major considerations needed to be taken as antigenic properties of the various potential subunits of a pathogen must be examined in detail to determine which particular combinations will produce an effective immune response within the correct pathway. Moreover, a chance the immunological memory might not be precise is present.


Polysaccharide vaccines

Streptococcus pneumoniae, and Haemophilus influenzae type b and N. meningitidis are common causes of pneumonia, meningitis, and other serious infections in children. They carry polysaccharide capsules which engage bacteria’s survival when carried in the nasopharynx and the blood during disease pathogenesis. The purified capsular polysaccharide-based vaccines were the first developed vaccines, such as the 23-valent pneumococcal polysaccharide vaccine that was licensed in 1983. However, polysaccharide vaccines are poorly immunogenic. The reason behind this is that they provide only short-term protection, and a reduction of immune response after repeated vaccinations (i.e. hyporesponsiveness) is found in some patients. Nonetheless, capsular polysaccharides are large molecules with repeated antigens that can be recognized by B cells. As a result, they can act without the requirement of T-cell help. Furthermore, polysaccharide vaccines are largely ineffective in children younger than two years old who are the major patients of invasive diseases with these pathogens since their immune systems are immature.


Conjugate vaccines

Connect or join is the meaning of conjugate. This type of vaccine is made of polysaccharide, sugar on the surface of many bacteria molecules, attached to a protein antigen to improve the ability of the immune system. Consequently, when the immune system can recognize these proteins it will have a strong response to the polysaccharide. Most of these are the attaching of the polysaccharide with diphtheria or tetanus toxoid protein. Nowadays, conjugate vaccines protect against Haemophilus influenzae type b (Hib), Pneumococcal, and Meningococcal infections.


Toxoid vaccines

Toxoid vaccines are made from toxoids (inactivated toxins) that are released by some bacteria; toxoids are not poisonous and trigger the immune response. The way that the immune recognizes and respond to toxoids is similar to what it does with antigen on the surface of bacteria. These vaccines are used to protect against Diphtheria (thick coating of dead tissue in the throat or nose) and Tetanus (painful tightening in the jaw muscles).


Viral vector vaccines

Viral vector-based vaccines don’t include antigens but the body produces them and modifies live viruses to carry DNA and deliver it into human cells. The DNA contains genetic code for antigen, when these vaccines are injected into the body they trigger an immune response. These vaccines combine the advantages in qualities of DNA vaccines and live attenuated vaccines. Viral vector vaccines carry DNA into a host cell for the production of antigen like DNA vaccines but can produce stronger immune responses, furthermore, it invades and replicates the host cells, much like a live attenuated vaccine. An example of this type of vaccine is the vaccine against Ebola.



VACCINE DEVELOPMENT


Process of designing and testing vaccines


Vaccine candidates go through an extensive and rigorous preclinical evaluation. After that, those vaccines are brought to humans. The process is divided into 3 main steps: Preclinical development, Clinical evaluation of vaccines, and Safety Monitoring.


1. Preclinical development

1.1 First step: Defining a Quality Control System for Vaccine Production

The producer needs to set up a quality control approach for the up-and-comer antibody, in compliance with a set of rules called ‘Good Manufacturing Practices’ (GMP) and in line with the guidelines of the National medicines agency. In addition, the vaccine will be named “released”. After validation, preclinical tests can start.

1.2 Second step: Establishing the Safety Profile of the Vaccine Before Testing in Humans

A panel of toxicity studies must be performed and animal studies are required to ensure safety. In addition, toxicity studies should be designed to mimic the intended use in the clinic, including relevant animal species, dosing schedule and method of vaccine administration. If any signal in preclinical toxicity studies is detected, preclinical testing should be required. For ethical reasons, when working with animals, the 3Rs concept of “Replace, Reduce, Refine” in the design of preclinical studies should be applied. The 3Rs stand for replacing the use of animals in research, reducing the numbers where the use of animals continues to be required, and refining the care of the animals to keep any pain and suffering to a minimum.

1.3 Third step: Application for approval for Human Trials The small-scale production process is developed and toxicity studies are completed. The sponsor will apply for approval to their competent authority. If the sponsor approves, clinical trials can start.


2. Clinical evaluation of vaccines

The pertinent regulatory authority, such as the EMA in Europe, or the FDA in the US reviews the preclinical data and the plan for the clinical trial. Human testing can begin. The sponsor applying describes the manufacturing and testing processes. The clinical development of a new vaccine candidate follows guidelines that have been issued by the EMA, FDA and the World Health Organization.

2.1 Phase 1

The target of Phase 1 considers is to get however much data as could reasonably be expected on wellbeing and to notice the insusceptible reaction after the organization of the immunization definition.

2.2 Phase 2

Phase 2 trials aim to provide further information on safety and immunogenicity. Phase 2 studies require hundreds of volunteers with the same characteristics (such as age and sex) as the people for whom the vaccine is intended. The FDA estimates that only one third of vaccine candidates usually move to the next phase.

2.3 Phase 3

Phase 3 trials aim to evaluate a vaccine candidate’s safety and effectiveness in a large cohort. This stage requires thousands to tens of thousands of healthy volunteers to identify potentially rare side effects. Moreover, those people can last for up to 4 years. Large-scale safety and efficacy studies are usually randomised, double-blind, and placebo-controlled. Viability is controlled by assessing the limit of the immunization possibility to forestall infection with the pathogen, prevent the disease, and induce immune response to the pathogen. If there are any issues, the regulatory authority can place a hold on the trial or ask the developer to pause or stop the trial. Significantly, studies can stop at any stage of the clinical evaluation if potential issues or risks are identified.


3. Safety Monitoring (Phase 4)

If Phase 3 preliminaries are effective, the vaccine developer can present a permit application to the important administrative power. If the drug is effective and safe, labelling is the next step Phase 4 will be carried out if the vaccine candidate has been approved for use. These involve the continuous, long-term monitoring of safety, effectiveness, and production. Observing the vaccine and production activities must continue for as long as a license for the product is held by the manufacturer. Any potential issues or side effects are reported by healthcare workers or individual consumers. As a result, these are carefully evaluated by an independent advisory group of vaccine safety experts and immunisation programmes may change as a result.


Vaccine development


Vaccine development takes more time , approximately 10-15 years to involve an experiment before the scientist reveals it to the public, so they will be testing the vaccine in animals and humans and see the effect from the vaccine efficiency.

The process has 5 steps to develop the vaccine.


Step 1 : Pre-Clinical Stage

Pre-medical levels use tissue or cell-lifestyle structures and animal checking to evaluate the protection of the candidate vaccine and its immunogenicity, or capacity to initiate an immune response. Animals used on this take a look at which includes mice and monkeys. These tiers can provide researchers a concept to broaden mobile reactions they could assume in humans. They will do the subsequent segment once they see the vaccines is safe

Researchers may also modify the candidate immunization amid the pre-medical kingdom to adapt to create it extra viable. They may additionally do venture research with the animals, that means that they vaccinate the animals after which they try to infect them with the goal pathogen.

The preclinical tiers take time lasting 1-2 years and generally contain researchers in personal industry.


Step 2 : IND Application

A support, typically a private company, presents an application for an Investigational New Drug (IND) to the U.S. Food and Drug Administration. The support depicts the assembling and testing measures, sums up the lab reports, and portrays the proposed study. An institutional survey board, addressing an organization where the clinical preliminary will be directed, should support the clinical convention. The FDA has 30 days to support the application.

When the vaccine is approved by the IND application, the next step is three phases of testing.


Step 3 : Clinical Studies with Human Subjects

Phase 1: Vaccine Trials

This first endeavor to survey the applicant immunization in people includes a little gathering of grown-ups, normally between 20-80 subjects. If the immunization is planned for youngsters, analysts will initially test grown-ups, and afterward slowly venture down the age of the guinea pigs until they arrive at their objective. Stage I preliminaries might be non-dazed (otherwise called open-name in that the scientists and maybe subjects know whether an antibody or fake treatment is utilized).

The objectives of Phase I testing are to evaluate the security of the competitor immunization and to decide the sort and degree of safe reaction that the antibody incites. In a small minority of Phase I immunization preliminaries, analysts may utilize the test model, endeavoring to contaminate members with the microbe after the trial bunch has been inoculated. The members in these investigations are painstakingly observed and conditions are painstakingly controlled. Sometimes, a constricted, or adjusted, variant of the microbe is utilized for the test. A promising Phase 1 trial will progress to test in the next stage.


Phase 2 : Vaccine Trials

A bigger group of a few hundred people partakes in Phase II testing. A portion of the people may have a place with bunches in danger of getting the sickness. These preliminaries are randomized and all around controlled, and incorporate a fake treatment bunch.

The objectives of Phase II testing are to consider the competitor antibody's wellbeing, immunogenicity, proposed portions, timetable of inoculations, and strategy for conveyance.

Phase 3 : Vaccine Trials

Successful Phase II applicant immunizations continue forward to bigger trail, including thousands to a huge number of individuals. These Phase III tests are randomized and twofold visually impaired and include the trial antibody being tried against a fake treatment (the fake treatment might be a saline arrangement, an immunization for another sickness, or some other substance).

One Phase III objective is to survey antibody security in a huge gathering of individuals. Certain uncommon results probably won't surface in the more modest gatherings of subjects tried in before stages. For instance, assume that an unfavorable occasion identified with a competitor antibody may happen in 1 of each 10,000 individuals. To recognize a huge contrast for a low-recurrence occasion, the preliminary would need to incorporate 60,000 subjects, half of them in the control, or no immunization, bunch.

Antibody adequacy is tried too. These components may incorporate 1) Does the competitor antibody forestall illness? 2) Does it forestall contamination with the microorganism? 3) Does it prompt creation of antibodies or different sorts of invulnerable reactions identified with the microorganism?

Next step : Approval and Licensure

After an effective Stage III preliminary, the antibody engineer will present a Biologics Permit Application to the FDA. Then, at that point the FDA will investigate the industrial facility where the immunization will be made and support the naming of the antibody.

After licensure, the FDA will keep on observing the creation of the antibody, including assessing offices and evaluating the maker's trial of heaps of immunizations for strength, security and virtue. The FDA has the privilege to direct its testing of producers' immunizations.

Post-Licensure Monitoring of Vaccines

A variety of systems monitor vaccines after they have been approved. They include Phase IV trials, the Vaccine Adverse Event Reporting System, and the Vaccine Safety Datalink.


Phase 4 : Trials

Phase 4 trial is another study that pharmaceutical corporations may direct after a vaccine is released. The maker may continue testing the immunization for wellbeing, adequacy, and other expected employment.


VAERS

The CDC and FDA founded The Vaccine Adverse Event Reporting System in 1990. the target of VAERS, as per the CDC, is "to identify potential signs of unfavorable occasions related with immunizations." (A sign for this example is proof of a possible unfriendly occasion that arises within the information gathered.) About 30,000 occasions are accounted for each year to VAERS. Somewhere within the range of 10% and 15% of those reports depict genuine clinical occasions that outcome in hospitalization, hazardous ailment, inability, or passing


VAERS is an intentional detailing framework that anybody, like guardians, medical services give or a companion of the patient presumed relationship among inoculation and unfriendly occasions may report that occasion and data this occasion to the VAERS. The CDC will then, at that time, survey the occasion and endeavor to determine if the unfavorable occasion was really caused .


The CDC expresses that they screen VAERS information to spot new, uncommon, or uncommon antibody unfavorable occasions Screen expansions in known unfavorable occasions Recognize potential patient danger factors for specific forms of unfavorable occasions.


Not all unfriendly occasions answered to VAERS are indeed led to by immunization. The 2 events can be connected in time because they were. Furthermore, it's plausible that not all unfavorable occasions taking place thanks to inoculation are accounted for by VAERS. The CDC expresses that numerous unfavorable occasions, as an example, expanding at the infusion site are underreported. Genuine unfriendly occasions, as per the CDC, "are presumably sure to be accounted for than minor ones, particularly after they happen shortly after inoculation, no matter whether or not they can be incidental and identified with different cause”.


VAERS has effectively recognized some uncommon antagonistic occasions identified with immunization. Among them are An intestinal issue after the most immunization for rotavirus was presented in 1999 and Neurologic and gastrointestinal illnesses identified with yellow jack immunization.


Vaccine safety datalink


The CDC founded this framework in 1990. The VSD is an assortment of connected data sets containing data from huge clinical gatherings. The connected information bases permit authorities to accumulate information about inoculation among the populaces served by the clinical gatherings. Analysts can get to the knowledge by proposing studies to the CDC and having them endorsed. The VSD incorporates a few downsides. For example, hardly any unvaccinated kids are recorded within the data set. The clinical gatherings giving data to VSD may have patient populaces that aren't agents of giant populaces as a rule. Also, the data comes not from randomized, controlled, dazed preliminaries but rather from real clinical practice. During this way, it may well be hard to regulate and assess the knowledge.


Quick Cycle Analysis may be a program of the VSD, dispatched in 2005. It screens ongoing information to give some thought to paces of antagonistic occasions in recently immunized individuals with rates among unvaccinated individuals. The framework is employed for the foremost part to screen new immunizations. Among the new immunizations being checked in Rapid Cycle Analysis are the formed meningococcal antibody, rotavirus immunization, MMRV antibody, Tdap immunization, and also the HPV immunization. Potential relationships between unfavorable occasions and inoculation are then concentrated further.


VACCINE HESITANCY

History


Vaccine hesitancy means the holdback or denial in accepting the vaccines regardless of their availability. The origin of vaccine hesitancy can be dated back to the invention of the smallpox vaccine in 1796. People started hesitating about getting vaccines as a result of anti-vaccine movements, which linked vaccination to certain diseases and disorders. For instance, the 1982 documentary film “Vaccine Roulette” portrayed the link between getting diphtheria, pertussis, and tetanus vaccine to developing neurologic disorders. Although this has been debunked by the fact that neurological disorders are caused by a genetic defect, the concerns of the public have already been raised. At that time, parents were worried about these side effects without considering that vaccines are responsible for the decline of certain diseases and being vaccinated would provide protection for their children’s general health (Rosenberg). This problem still exists today as it is easier for misinformation to spread on the internet. Nevertheless, misinformed scientific information or conspiracy theories are not the only factors that cause the delay of vaccine acceptance. Another main issue relates to structural factors such as health inequalities, socioeconomic backgrounds, or discriminations against minorities, which set the barriers to gain access to vaccines. As a result, the issue of vaccine hesitancy became one of the top ten threats to global health according to the World Health Organization (WHO).

COVID-19 vaccine hesitancy around the world


Cost, efficiency, duration of protection, and safety are not the only major factors that influence the vaccine’s utility. Vaccine acceptance plays a significant role in successfully controlling and approaching the end of the pandemic. There is a great variation of vaccine acceptance in different countries around the world. As of May 2021, in 79 out of 117 countries, the number of people willing to get vaccinated was below 70 percent, the minimum percentage required to stop the virus from circulating aka racing herd immunity. According to the research, low COVID-19 vaccine acceptance rates were witnessed in the Middle East, Europe, and Russia in which countries with the lowest acceptance rate included Kuwait (23.6%), Jordan (28.4%), Italy (53.7), Russia (54.9%), Poland (56.3%), US (56.9%), and France (58.9%). In contrast, there is a high COVID-19 vaccine acceptance ratio in East and Southeast Asia: Ecuador (97.0%), Malaysia (94.3%), Indonesia (93.3%), and China (91.3%). Eight surveys among healthcare workers show a 27.7 % vaccine acceptance rate in the Democratic Republic of Congo; 78.1% in Israel. (Sallam, 2021).

Despite the large variability reported in various countries and regions around the world, as vaccination proceeds, attitudes towards it may change. For example, in the U.S. , the vaccine acceptance rate rose from slightly more than half to 74 percent of adults between 2020 and March 2021. As of 11th June, about 172.8 million people have been immunized with one dose, at minimum, for Covid-19 vaccine, including about 142.1 million people who have been fully vaccinated by Johnson & Johnson’s single-dose vaccine or the two-dose series made by Pfizer-BioNTech and Moderna in the U.S. Evidently, decent vaccine administration decreases vaccine hesitancy among citizens. The same is anticipated in other countries as long as the collaborative efforts of governments, the health sector, and media sources are made. Proper management, information, guidelines, and choices of vaccine are vital to creating vaccination trust among the general public.


COVID-19 vaccine hesitancy in Thailand


Vaccines have been a very controversial topic among Thais. Since the mass inoculation program has started, vaccine hesitancy has increased rapidly. The three main reasons for the complaints are the delays of the vaccine, reliance on Sinovac, and the manufacture of AstraZeneca. According to the poll made by Yougov, from January to May the willingness to get the shots decreased from 83% to 66% due to the following reasons. The percentage made Thailand falls behind many ASEAN countries such as Vietnam and the Philippines on the willingness to get vaccines which are going to affect the rate of vaccination in Thailand. In June, only 2. 3% of Thailand's population was fully vaccinated and 6.3% of them already received one dose. According to the Suan Dusit Poll, more than 50% are afraid of the side effects of vaccines. The government and many doctors have confirmed that the side effects are coincidental and it is better to stick to the plan and get the vaccines to go back to normal as soon as possible. From millions of people, there are only 28 deaths and most of the deaths are from AstraZeneca because it is a live vaccine and not suitable for young people. Many people are also questioning if the AstraZeneca vaccines that are made in Thailand reached the standard or not. Even though it is a very small death rate, it does bring a big challenge for the government. The government has targeted to vaccinate 70% of the population by the end of the year and now 7.8 billion people have registered for the vaccines. The government has come up with the solution by giving free vaccine shots and many people have joined the program but because Thailand cannot produce the big dose of vaccines, there are many delays of the appointment dates which made many citizens upset. Not only that the doses are not enough but many Thais do not like Sinovac and AstraZeneca as much as Pfizer and Moderna because the last two have more coverage but due to the relationship between China and Thailand, it is easier and faster to import those two vaccines. Some Thai celebrities do not trust the government’s choice on vaccines at all and flew to the United States just to get vaccinated and posted it on social media which created a bigger fuse. Several Thais also called Sinovac’s, “Shenzhen vaccines” a reference to a city in China that is known for cheap knock-off products. If the Thai government did not find a way to confirm the safety of the shots and to make the importation faster, the goal of vaccinating 70% of the population may not be reached by 2021 and Thailand’s economy will recover slower than the other countries.


EFFECTS OF VACCINE


What causes vaccine effect?

Vaccines may result in side effects, which is the body's natural response to develop the immune system.


Vaccine ingredient

  • Formaldehyde

Formaldehyde is normally found in humans. It is used in manufacturing some vaccines such as the hepatitis A vaccine.

  • Thimerosal

Thimerosal contains ethylmercury that is cleared from the human body faster than methylmercury, which is found in fish. Thimerosal is used in medical products and is very safe despite allergic reactions in some people.

  • Antibiotics

Antibiotics help prevent bacterial contamination and fungus growth.

  • Adjuvants

Adjuvants are substances that help improve the immune system's response. Aluminum is an example of adjuvants.

  • Aluminum

Some vaccines put aluminum salts or aluminum gels for a strong immune system response to antigens. 50% of aluminum will be eliminated before 24 hours, more than 75% will be eliminated within 2 weeks.


Factors that impact the effects of vaccines

  • Age

An important factor that impacts vaccine responses.

  • Sex

Females antibodies are more likely to respond to IPV, rabies, and TIV vaccination. Meanwhile, males have a higher antibody response to diphtheria, MCV-A, PCV7, PPV23, and tetanus vaccination.

  • Genetics

Blood groups are significant receptors for microorganisms. They can adjust the innate immune response to infection.


How often do side effects happen?

Side effects are quite common, occurring possibly 50 to 70 percent of the immunized people. However, adverse cases are rare and unexpected, like clotting disorders.


Side effect

Vaccine effects could impact in different ways and different rates of pain, similar to other medications or supplements. This may results from different factors such as the vaccine itself and the patient. Effects of vaccines can be classified into two types: common effects and allergic reactions (serious effects).


Common effects

The common effects are the side effects that usually happen after you get the vaccine. These symptoms will cause mild pain that won't disrupt daily activities and it is normal to occur. Common effects may include pain, swelling, or redness where the shot was given Mild fever, chills, feeling tired, headache, muscle, and joint aches may be expected as well. Children may also be fussier than adults. However, the symptoms tend to last for only a few hours or a few days. Also, having side effect means that the body is starting to build immunity (protection) against a disease, called an inflammatory response or reaction.


Allergic reactions

Serious side effects or Allergic reactions are extremely rare. For example, if 1 million doses of a vaccine are given, 1 to 2 people may acquirea severe allergic reaction, and it usually happens shortly after a person receives the vaccine. Allergic reactions can include difficulty of breathing, swelling of the face and throat, fast heartbeat, bad rash all over the body, dizziness, and weakness. If you experience any of these symptoms you should call your healthcare provider or emergency service, or visit the nearest hospital too.

Stress-related reactions

People who are not ready to receive their vaccines might unintentionally develop anxiety that could cause them some other symptoms. Stress-related reactions may include turning pale and sweatingt, feeling lightheaded or dizzy, feeling numbness or tingling, starting to breathe very quickly, and feeling the loss of sensation in the face, hands, or feet. However, these symptoms could be self-controlled by breathing slowly and deeply, while counting to 10.


Side effects of well-known vaccines


Pfizer COVID-19 vaccine

  • The first dose of Pfrizer

    • Pain at the injection site

    • Fatigue

    • Headache

    • Others (body aches, chills, joint pain, swelling)

  • Second dose of Pfizer

    • Pain at the injection site

    • Fatigue

    • Headache

    • Body aches

    • Chills

    • Fever


Johnson & Johnson’s Janssen COVID-19 vaccine

  • Pain, redness, and swelling at the injection site

  • Tiredness

  • Headache

  • Muscle pain

  • Chills

  • Fever

  • Nausea


AstraZeneca COVID-19 vaccine

  • Common side effects

    • Tiredness

    • Headache

    • Muscle pain

    • Fever

    • Redness

  • Rare side effects

    • Sleepiness

    • Rash

    • Dizziness

    • Sweating

  • Very rare side effects

    • Very unusual blood clots

    • Capillary leak syndrome


Sinovac COVID-19 vaccine

  • Commmon side effects

    • Pain at the injection site

    • Elevated blood pressure

    • Headache

    • Dizziness

    • Rash

  • Rare side effects

    • Unusual stroke-like

    • Drowsiness

    • Numbness in the limbs


Yellow fever vaccine

  • Common side effects

    • Soreness

    • Redness

    • Swelling

    • Fever

    • Headache

    • Muscle aches

  • Rare side effects (more likely in people over 60 years of age)

    • Faint

    • Allergic reactions that may lead to death

Human Papillomavirus (HPV) vaccine

  • Pain, redness, and swelling at the injection site

  • Feverr

  • Dizziness

  • Fainting

  • Nausea

  • Headache

  • Tiredness

  • Joint pain

  • Fertility problems


Vaccine defrayal

The government or vaccine companies have to guarantee that the vaccine is good enough, and take responsibility if anything happens to their patients, who take a risks. The defrayal has to compensate patient physically and mentally. However, the case does not happen much asthe vaccine experimental progress takes time before it is ensured that the vaccine is fully developed. However, for urgencies like the COVID-19 pandemic, vaccines are an important solution that can help humans. This means that the shorter experiment progress may lead to less safety. The Singaporean government said that whoever gets severe side effects from the vaccine would be ameliorated to ten-thousand-dollar Singapore or about 250,000 Baht, and would get 5,250,000 Baht if vaccine results in death. Also, in Japan, the government will ameliorate 44.2 million Yen or about 12 million Baht for the death, and 200,000 Yen or about 60,000 Baht for holding funerals, which builds reliance among citizens. For in Thailand, 400,000 Baht will be given for each death from vaccine, 240,000 for permanent disability, and 100,000 for the injuries.



VACCINE AND COVID-19

Coronavirus vaccines have been developed by many scientists all around the world. For the past 2 years, the vaccines went through many processes and tests for efficacy and safety before approval to vaccine humans. The vaccines that are already approved like Pfizer, Johnson & Johnson, Moderna are given to people nowadays.


AstraZeneca COVID-19 vaccine

AstraZeneca was designed by the University of Oxford and produced by a British-Swedish company. With a 76 percent efficiency, AstraZeneca has been approved in moreover 110 countries. Because they only need to be refrigerated rather than frozen, it can result in harsher side effects than mRNA vaccines, plus a low price.

To receive the vaccine, two doses of the AstraZeneca vaccine are required. People who have taken the first dose and without any serious side effects can be given the second dose. The health workers who are at high risk to get the coronavirus, older adults, including 65 years or more should be given the vaccine. Those who are under 65 are allowed to take the vaccine but the person has made an informed decision based on an understanding of the risks and benefits.


Moderna COVID-19 Vaccine

Moderna mRNA-1273 was found during the pandemic and developed by the US Biotech which is based in Cambridge. After they had gone through phase three, the result suggested efficacy against the COVID-19 is 94.1%, starting 14 days after the first dose. By sending the virus’ genetic code in the body called “mRNAs”

The recommendation of Moderna at the schedule of 2-dose, which is 28 days apart. Persons who should be vaccinated are persons with medical conditions associated such as diabetes, pulmonary, liver, or kidney disease, who live with HIV are highly recommended, and aged 18 or older, health workers.


Johnson & Johnson’s Janssen COVID-19 Vaccine

JNJ-78436735 was developed by Janssen Pharmaceuticals Companies of Johnson & Johnson. By their dedicated teams and unprecedented collaborations all around the world, they were the first ones who shared a single dose of COVID-19 Vaccines to the public to fight against COVID-19 and the dire outcome of hospitalization and death.

J&J provides COVID-19 vaccines in individuals aged 18 or older and a single shot is required 28 days after inoculation has an efficacy of 85.4% against severe disease and hospitalization. In terms of clinical, a single-dose Janssen Ad26.COV2.S has an efficacy of 66.9% against symptomatic moderation.

In March and April 2021, there have been over 600 reports about fainting and anxiety-related events after vaccination’s J&J. It’s reported at a rate of 0.05 per 100,000 doses, compared to 8.2 episodes per 100,000 doses of J&J. Nearly a quarter of patients, who get J&J, report a needle aversion of fainting post-vaccination.


Pfizer-BioNTech COVID-19 Vaccine

BNT162b2 was an mRNA-based COVID-19 Vaccine developed by the partnership of Pfizer and German-manufacturer BioNTech. Pfizer is authorized for emergency use in the United States and other countries. It is recommended for people aged 12 years and older. To be fully effective, two shots of vaccinations are required 21 days apart. Based on the laboratory results of efficacy for each vaccine, Pfizer is 95 percent efficacy in preventing infection in people aged 16 years and older with no prior infections. Moreover, In clinical trials, Pfizer was also highly effective in people aged 12-15 years.


Covid-19 Vaccines in Thailand

COVID-19 vaccines available in Thailand include AstraZeneca and SinoVac vaccines.


1. AstraZeneca vaccine

The supply chain of AstraZeneca in Thailand was established in partnership with Siam BioScience, a Thai manufacturer specialized in biopharmaceutical medicines. The first doses of AstraZeneca’s COVID-19 vaccine which was manufactured by Siam Bioscience have been approved for quality and safety by both local and international testing laboratories. It is proved in people aged over 18. The vaccination course consists of two separate doses of 0.5 ml each. The second dose should be administered 4-12 weeks apart.


2.SinoVac or CoronaVac Vaccine

Thailand has imported millions of vaccine doses of the vaccine of SinoVac also known as CoronaVac from China. This vaccine has been recommended in people aged between 18-59.SinoVac vaccination course consists of two separate doses of 0.5 ml each. The second dose should be injected 2-4 weeks apart from the first dose.

Will we test positive after we get the COVID-19 vaccine?


None of the researchers and recommended vaccines cause the positive on the viral test. If you develop an immune response to vaccination, which is the goal, you may test positive on some antibody tests.



WORK CITED


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