Important facts about COVID-19 vaccines you should know

Let's counter misinformation about COVID-19 vaccines by equipping yourself with scientifically accurate answers about COVID-19 vaccines.

Facts about COVID-19 vaccines you should know
UNICEF Viet Nam\Vu Le Hoang
22 April 2022

1. Why is booster dose of COVID-19 vaccine necessary?

A booster dose is recommended 3-6 months after completing the primary series to sustain immune protection against COVID-19 and its variants, including Omicron. 

Boosters should be prioritized for those at the highest risk of severe illness due to COVID-19. This includes older adults, immunocompromised people, health workers, people with underlying health conditions, pregnant people, essential workers and other vulnerable populations. 

Even after vaccination, it’s important to continue other protective measures like keeping a safe distance and wearing a mask.

2. Do breakthrough cases mean that the vaccines aren't working?

Existing COVID-19 vaccines are very effective for preventing severe disease and death. But no vaccine provides 100% protection. It is the same as for other vaccines, like influenza (i.e., flu) 

Over time, protection can reduce, which means that you can still get infected with COVID-19 after being vaccinated. If you do get infected after vaccination, often it will be with mild symptoms, or perhaps no symptoms at all. But be aware that you can still pass the virus onto others. 

This is why booster doses are being offered so that people can get extra protection against COVID-19 and its variants. 

But vaccination isn’t enough. We should continue to keep a distance from others, wear a mask, avoid crowded spaces, keep our hands clean, cover sneezes and coughs, and open windows where possible. 

3. Can vaccines protect against variants?

Current COVID-19 vaccines continue to provide high levels of protection against severe disease and death. We must not put off getting vaccinated because of our concerns about new variants, and we must proceed with vaccination even if the vaccines may be somewhat less effective against some of the COVID-19 virus variants. We need to use the tools we have in hand even while we continue to improve those tools.

It is also important to continue practicing safety precautions to protect yourself and others. These precautions include avoiding crowded spaces, physical distancing, hand washing and wearing a mask.

We are all safe only if everyone is safe.

4. What are the ingredients of COVID-19 vaccines?

Vaccines contain tiny fragments of the disease-causing organism or the blueprints for making the tiny fragments. They also contain other ingredients to keep the vaccine safe and effective. These latter ingredients are included in most vaccines and have been used for decades in billions of doses of vaccine.

Ingredients in the labels of vaccines are usually found naturally in the body, the food we eat, and the environment around us. The amounts in vaccines are very small and will not “poison” or harm the body.

Each vaccine component serves a specific purpose, and each ingredient is tested in the manufacturing process. All ingredients are tested for safety.

5. Can pregnant women get vaccinated with a booster dose?

COVID-19 vaccines are safe for people who are pregnant, breastfeeding, trying to get pregnant, or might become pregnant in the future.

Pregnant people are at higher risk of serious illness if you get COVID-19. You are also at higher risk of delivering your baby prematurely if you get COVID-19. Evidence on the safety of COVID-19 vaccines during pregnancy has been growing, and no safety concerns have been identified.

For more information about receiving a COVID-19 vaccination while pregnant, speak to your healthcare provider.

6. How do COVID-19 vaccines work?

Vaccines work by mimicking an infectious agent – viruses, bacteria or other microorganisms that can cause disease. This ‘teaches’ our immune system to rapidly and effectively respond against it. 

Traditionally, vaccines have done this by introducing a weakened form of an infectious agent that allows our immune system to build a memory of it. This way, our immune system can quickly recognize and fight it before it makes us ill. That’s how some of the COVID-19 vaccines have been designed.

Other COVID-19 vaccines have been developed using new approaches, which are called messenger RNA, or mRNA, vaccines. Instead of introducing antigens (a substance that causes your immune system to produce antibodies), mRNA vaccines give our body the genetic code it needs to allow our immune system to produce the antigen itself. mRNA vaccine technology has been studied for several decades. They contain no live virus and do not interfere with human DNA.
For more information on how vaccines work, please visit WHO.

7. What are possible side effects after receiving the COVID-19 vaccine?

Vaccines are made to help develop immunity, protecting the body from the risk of disease. Although side effects do not usually arise during the immune system, in many cases, some mild to moderate side effects can appear and go away after a few days. Some mild to moderate side effects that may be experienced after vaccination include:

  • Injection site pain (also known as a sore arm)
  • Mild fever
  • Tiredness
  • Headache
  • Muscle or joint pain
  • Chills
  • Diarrhea

If any of the symptoms persist for more than a few days, or any other reaction occurs, contact your health provider immediately

8. How is the COVID-19 vaccine safely transported and stored?

Vaccines against COVID-19 are transported in a cold chain. Each stage in the transportation includes airplanes, trucks, refrigerators, and coolers, which help preserving vaccines in the best condition.

9. Is natural immunity better than COVID-19 vaccination?

While people who recover from COVID-19 may develop some natural immunity to the virus, we do not yet know how long it lasts or how well you are protected.You can be infected with SARS-CoV-2 a second or third time, which makes getting vaccinated even more important. Natural immunity can weaken over time and be strengthened with vaccinations. COVID-19 can cause serious complications and can be deadly.

Meanwhile, vaccines allow your body to build immunity without the damaging effects the actual diseases can have.

10. Can COVID-19 vaccines cause miscarriage or stillbirth?

COVID-19 vaccines protect against severe illness and pregnancy complications. Millions of pregnant people around the world have been vaccinated against COVID-19. Vaccination is safe and recommended for those who are pregnant, breastfeeding, or trying to become pregnant in the future.

Some people have falsely claimed that COVID-19 vaccines cause pregnancy complications in an attempt to discourage vaccination during pregnancy.

Researchers have studied hundreds of thousands of pregnancies around the world and found no evidence that COVID-19 vaccines increase the risk of miscarriage or stillbirth. A study of over 157,000 pregnancies found no increase in adverse pregnancy outcomes, including premature birth, stillbirth, low birth weight, or post-natal complications in vaccinated mothers. The data have also confirmed that the vaccines reduce the risk of COVID-19 hospitalization and death during pregnancy.

11. Can COVID-19 vaccines impact fertility?

There is no evidence that COVID-19 vaccines affect fertility in women or men. You should get vaccinated if you are trying to become pregnant or plan to in the future.

Myths about vaccines and fertility have persisted for decades but have never been substantiated by scientific research. There is no evidence that the COVID-19 vaccines will affect fertility or prevent pregnancy.

Many participants in the COVID-19 vaccine trial got pregnant during or after the trial with no safety concerns. Data collected by health authorities and numerous studies have found that COVID-19-vaccinated people have no issue conceiving and do not have any increased risk of adverse pregnancy outcomes, including miscarriage or stillbirth.

12. Are COVID-19 vaccines safe for breastfeeding women?

If you are breastfeeding you should take the vaccine as soon as it is available to you. COVID-19 vaccines are very safe and there is no risk to the mother or baby. The antibodies that you have after vaccination may go through the breast milk and help protect your baby.

13. Do COVID-19 vaccines cause hair loss?

Vaccines are the best protection against COVID-19 infection, severe illness, and death. COVID-19 is a serious disease that infected over half a billion people and killed over 6.3 million people worldwide. There are no reports of hair loss following COVID-19 vaccination in people without a prior history or high risk of hair loss. There is some evidence that COVID-19 infection can cause sudden hair loss.

14. Do Covid-19 vaccines cause memory loss?

No scientific evidence supports the claim that COVID-19 vaccines cause memory loss.

To date, there appear to be only two published reports of individuals who experienced memory loss after COVID-19 vaccination: a patient with dementia who had reported memory impairments in the five months before vaccination and a patient who experienced memory impairments six days after COVID-19 vaccination that resolved within 24 hours. In both cases, vaccination cannot be determined to have caused memory loss. Notably, memory loss and other cognitive impairments are well-documented symptoms of long COVID.

COVID-19 vaccines were rigorously tested in thousands of trial participants and have been safely administered to over two-thirds of the world’s population. At this point, if extremely rare, one-in-a-million side effects exist, they would have‌ emerged already.