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How Safe Is the COVID-19 Vaccine?

by Gauri Kolhe

Vaccination is tool which helps the immune system to develop the protection and prevention against many different types of infectious diseases.

In general vaccine contains virus or microorganism in weakened, killed or lives form that stimulates adaptive immunity of body which fights against the microorganism or virus.

Covid-19 leaves the world in havoc due to which Food and Drug Administration (FDA) in the United States has given emergency use authorization (EUA) of two vaccines against the covid virus that causes COVID-19.

Vaccines that approved by FDA are as Pfizer- BioNtech and Moderna vaccine. Johnson & Johnson also applied for the authorization for the emergency use of their single dose vaccine.

The COVID-19 vaccine is useful and vital tool in order to stop the spread of the new corona virus that is known as SARS-CoV-2. The concern regarding the safety of using COVID vaccine and the potential short and long term side effects are wondering you.

Prior to use any medicine or vaccine goes through the various phase of clinical trials. After seeing the emergency condition FDA approves the emergency use of vaccine.

This article is related with the various safety concerns of covid vaccine, possible side effects and how vaccine works.

Development of the COVID vaccine

Usually vaccine development takes several couple of years. Despite this fact, covid vaccine has been developed in a short time.

As a matter of fact, according to the World Health Organization (WHO) over 200 potential covid-19 vaccines are in the development process as of December 2020 in which at least 52 of the vaccines have entered in the clinical trials in humans.

This fast development of covid vaccine done so quickly is the center of attraction and how do they do it? In this article we’ll have look regarding this.

Worldwide Scientific collaboration

After the spread of corona virus as soon as this new corona virus was identified and the sequence of genetic material identified, many scientific organizations started to collaborate with each other and start studying. With this effort they shared important research results with other scientists.  

This highly standard collaboration helped in the distribution of the knowledge regarding corona virus throughout the medical and scientific communities.

The knowledge included how it spreads, causes illness, and potential side effects of the corona virus and the most important the treatment.

Previously existing research


As the corona virus is new, the technology that used to develop COVID-19 vaccine may seem new also. However, some of these technologies actually have been exist for some time.

Pfizer- BioNtech and moderna vaccine are developed using the new technology of mRNA vaccines.  Scientists had been studying this method to develop the vaccines for other viruses prior the epidemic pandemic. This previously existing technique help the scientists to develop vaccines for the SARS-CoV-2.

Funding for the research

Any drug discovery and development need a huge funding so as Vaccine development and costly. The main reason behind this is that vaccine development requires an abundance of testing of the effectiveness as well as safety.

The cost of the vaccine development starts increasing rapidly when it enters in the human clinical trials.  

Clinical trials consist 4 phases of trials, three phases of which must show the effectiveness and safety before the vaccine approved or authorized. With the progress of the trial phases the number of the subjects grows and so do the costs.

In Early days of the pandemic, the funding was came from the both public and private sources permit the companies to conduct research in effective way that necessary for the vaccine research and clinical trials.


Timeline acceleration

Usually the stages of vaccine development and testing occur in many stages one after other which takes a lot of time. Due to the emergency in the pandemic, some of these timelines were accelerated in order to shorten the duration of vaccine development.

Companies accelerated the sped of the manufacturing the vaccines additionally while they performed the clinical trials.

This development creates a huge financial risk to those companies whose vaccine was not proofed as effective and safe while in case of successful effectiveness and safety, vaccine was ready to use.

Despite these the universal fact is that all covid-19 vaccines need to undergo further rigorous testing protocols that aims towards the effectiveness as well as safety.

However vaccine development happening fast, scientific standards and integrity don’t compromise. Research organizations and companies still need to present solid data from the human clinical trials.

The short-term effects of the vaccine

Covid-19 vaccine shows the short term as well as long term side effects. The short term side effects of the vaccines are similar to corona virus effects. These side effects start within one or two days of dose administration. The short term side effects are:

  • Headache
  • body aches and pains
  • fever
  • Pain, redness, or swelling at the injection site
  • fatigue
  • chills
  • nausea
  • swollen lymph nodes

Feel the above given symptom is pretty normal after getting covid-19 shot. Showing the symptoms is unpleasant but this is good sign that you body starting to generate an immune response against corona virus.

As these signs are unpleasant they can be typically mild or moderate and lastly fad away after a few days. Fatigue and headache and fever are the more common symptoms that can be seen after getting second dose.

Serious short-term side effects of vaccine

Although most of the people experience mild or moderate symptoms, some of the people suffer from the more serious short term side effects after getting covid-19 shots.  These side effects include some immediate allergic reactions and a severe allergic reaction called as anaphylaxis.

These immediate reactions usually occur within the 4 hours of getting the vaccine and show the symptoms like wheezing, hives, swelling. Anaphylaxis reactions occurs aftr a little time after receiving the vaccine. Symptoms of anaphylaxis includes

  • Swelling
  • Feeling dizzy or faint
  • trouble breathing
  • Low blood pressure (hypotension)
  • tightening of the throat
  • abdominal pain
  • Nausea or vomiting
  • diarrhea
  • Hives
  • A rapid heartbeat
  • a feeling of doom

In order to make sure that you don’t develop any of these symptoms you need to monitor after at least 15 minutes after getting covid-19 vaccine.

The long-term effects of the vaccine

The use of covid vaccine Pfizer BioNtech and moderna have been only in the United States since December 2020 the long term side effects was unknown.

Due to emergency and emergency authorization use people began to get the covid-19 vaccine, studies and surveys are in continue state to evaluate the safety and effectiveness of vaccine without  LONG TERM side effects. The study also focuses on the immunity lasting duration.

Related Questions about Vaccines

What is the mRNA in actual?

Both the Pfizer-BioNtech and Moderna vaccines are prepared by mRNA technique and consist of a piece of genetic material called mRNA. mRNA provides the instructions to the cells of your body on how to make proteins for further.

mRNA is the genetic material that occurs in very cell of human body and cells use this mRNA to produce many type of the proteins which is necessary for the human body.

The mRNA present in the covid vaccine contains the instructions to make spike protein which is a viral protein. This protein found at the surface of novel corona virus and virus uses this protein to enter the human body.

The mechanism of protection includes the recognition of the spike protein by your immune symptom. When you get your vaccine, body recognize the spike protein as an invader and body starts to produce antibodies against the corona virus spike protein.

Events happen on the administration of vaccine.

After getting Pfizer-BioNtech or Moderna vaccine, the mRNA present in the vaccine can enter the cells in your body. These cells begin to produce the spike protein. The cells of your immune system notice the spike proteins and recognize them as a foreign material.

Due to protection tendency immune system starts producing an immune response to the proteins and produces the antibodies.

After that if you have any exposure to corona virus than you body recognize that as an invader and this will be destroy before causing the illness.

Simply putting your body already knows to produce antibodies against corona virus which neutralize the effect of corona virus and fight against it after getting vaccine.

Body takes weeks to develop the immunity so you could be infected right before or right after getting the vaccine which is needed to remember.

 Do vaccine has the ability to change your DNA?

When you are in the middle of conversation regarding corona you may have heard about the concerns about the COVID-19 vaccine affecting your DNA.

Well this is not possible.  Human body contains DNA in the nucleus, the center part of the cell and nucleus is separated from other area of cells. Cell produces mRNA every day within the nucleus and transported outside the nucleus to make protein.

After producing protein mRNA destroyed itself. This similar thing happens in case of covid-19. mRNA of vaccine remain outside of the nucleus and it will get destroyed after producing the spike protein.

Avoid getting the vaccine

Some people should have avoid to get  the shot of Pfizer-BioNTech or Moderna COVID-19 vaccines. This includes anyone who’s had:

  • Either a prior severe or immediate allergic reaction to any of the ingredients in the vaccine
  • Either a severe or immediate allergic reaction after getting the first dose of the vaccine
  • A previous allergic reaction to polyethylene glycol (peg) or polysorbate

Can children get the vaccine?

Children cannot get the corona vaccine as Pfizer-BioNTech and Moderna vaccines are currently authorized only for use in people 16 and older, and 18 and older, respectively.

In order to make use of children it needs some more clinical trials.

Getting vaccine in underlying health condition?

If you are suffering of any underlying health conditions, you should get concern to your doctor as these underlying conditions can lead higher risk of serious covid-19 complications.

Getting vaccine if you’re pregnant or breastfeeding?

If you are pregnant or a breastfeeding mother that yes you can receive the vaccine. Just talk to your doctor and health provider.

If you’ve had COVID-19 then is it safe to get vaccine?

You may be wondering if you still need to get the vaccine if you’ve already had COVID-19. Surprisingly yes you need vaccine and it is safe for use.

After having covid-19 natural immunity lasts for how much time is not known by the scientists so researches are ongoing to confirm this. A study in 2021, 188 people had recovered covid-19 marked immunity up to 8 months after getting infected.

You could have infected again and number of repeated cases far so documented. Vaccination can help prevent repeat infection.

Is there any Need to taking precautions after getting vaccinated?

Taking precaution is most important to prevent covid-19 infection. If you have wondering that yu still need to take precautions after getting vaccine then the response is yes you need to take precautions after vaccination.

You need to wearing a mask, practicing physical distancing, frequent hand washing and avoiding the crowded area.

Scientists still don’t know that you can still transmit the virus to others after you have been vaccinated so it is necessary to take these precautions.


Covid-19 vaccine developed in as short period of time while regular process needs couple of years. So the effectiveness and the safety of the vaccine concern the scientists.

This development was possible due to scientific collaboration, time acceleration, increased funding and a large body of previous researches.

Around 200 of the vaccines were developed and about 52 vaccines have undergone the clinical trials in human subjects.

The currently using vaccines are still under vigilance and going through much scientific study covid-19 vaccine are made by putting mRNA in the vaccine, the mRNA occur on the surface of corona virus and responsible for producing the viral protein i.e. spike protein. In response of this, body starts to produce antibodies.

When it comes to the safety, vaccine has some short term mild and moderate side effects which include headache, fever, fatigue, cold etc while serious short term side effects include immediate reactions and anaphylaxis that responses like hives, swelling.

Even after getting infected you need to get vaccine to prevent repeated infection. You need to concern your doctor in case of having underlying health condition, pregnancy and other problems.

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