Covid-19 Vaccine

1. Questions and Answers

1. Does the COVID-19 vaccine work?

Ans: Yes. The Pfizer and Moderna vaccines are about 95% effective, AstraZeneca's is about 70% overall, while Johnson and Johnson is 66.1% globally, 72% in the United States of America, and 86% against severe disease.

2. How do the vaccines work?

Ans: The vaccines from Pfizer and Moderna use a technique known as mRNA, or messenger RNA. These vaccines give instructions for our cells to make a harmless piece of what is called the 'spike protein,' according to the CDC. This protein is found on the surface of the coronavirus that causes COVID-19. Once these vaccine instructions, or mRNA, are injected, your cells use it to make the spike protein; then the instructions are broken down and eliminated. The protein piece is displayed on the cell surface, triggering the immune system to make antibodies against it, just as it would if it were exposed to the real coronavirus that causes COVID-19. In this way, the body learns how to protect itself when and if the real virus shows up. The mRNA vaccines don't use the live virus that causes COVID-19, nor does the mRNA get into the cell's nucleus, which is where our DNA (genetic material) is stored. The AstraZeneca vaccine is made from a weakened version of a common cold virus, the adenovirus, taken from chimpanzees. The adenovirus is genetically altered so it can’t reproduce itself. The vaccine is combined with genes of the spike protein to trigger production of antibodies against it, which allows the immune system to destroy the COVID-causing virus.

3. How many doses do you need?

Ans: Two doses are needed for each of the three “frontrunner” vaccines from Moderna, AstraZeneca, and Pfizer.

4. What is the interval between doses?

Ans: For the Moderna and AstraZeneca vaccines, the two doses are given 4 to 6 weeks apart. For Pfizer's vaccine, the two doses are given 3 to 6 weeks apart. The U.S. government and the manufacturers have partnered to make sure there are enough doses available for everyone to get two.

5. What happens if you don't take the second dose?

Ans: Protection is assumed to be less. In data that Moderna submitted to the FDA before its Dec. 17 review for its request for emergency use authorization, for instance, its analysis suggested that the first dose provides protection from getting COVID-19, but the data did not allow for a “firm conclusion," the FDA says. Both the Pfizer and Moderna vaccines are believed to be around 50% effective after just one dose.

6. After the required doses, how long until it takes effect and provides protection?

Ans: It takes about a week after the second dose. Once the second dose kicks in, both the Pfizer and Moderna vaccines have shown in studies to be about 95% effective.

7. How well do the vaccines work?

Ans: Overall, the Pfizer and Moderna vaccines are about 95% effective. AstraZeneca's is about 70% overall, but that protection was found to be higher in some groups.

8. How long does the protection last?

Ans: Because the vaccines are new, this is not yet known for sure. Based on other viruses that are similar to the coronavirus that causes COVID-19, the COVID-19 vaccines that are shown to be highly effective might protect people for a few years.

9. What is the advantage of getting a vaccine?

Ans: If you are at risk it prevents from death. It does not prevent you from getting infected, but immunity from the vaccine helps you fight the virus if exposed, and reduced risk of developing the illness and its consequences.

10. Will I test positive for COVID-19 after getting vaccinated?

Ans: No. Getting the vaccine will not make you test positive for COVID-19 on a rapid test or a PCR test. If you test positive and it’s an accurate result, you were likely exposed before you got the vaccine or before the protection kicked in.

11. What about side effects?

Ans: People should expect to have some side effects, similar to what some people report after getting a flu vaccine, according to experts meeting recently with the CDC. These experts said to expect temporary side effects such as soreness in your arm where you got the shot, fatigue, body aches, and perhaps a fever. At least two people getting the Pfizer vaccine in the U.K. had severe allergic reactions, promoting the British government to tell those prone to anaphylaxis-like reactions not to take it. As for serious side effects, it's too soon to know about rare side effects. That is because phase III trials do not supply enough information about rare side effects. That will become evident, if it occurs, as more people are vaccinated. Even so, doctors’ advice it is not a reason to avoid the vaccine. As millions of doses are distributed, if there are very rare side effects, they are expected to show up in a very short time frame.

12. After the FDA's emergency authorization (EUA) is granted, are the vaccines still tracked?

Ans: Yes. The United States Food and Drug Administration (FDA) expects the manufacturers to continue their clinical trials to find out more about how safe and effective they are, and pursue full FDA approval or licensure. The EUA, which is different from FDA approval, is based on the FDA's evaluation of available evidence, assessing risks and benefits. It issues the EUA if the benefit-risk balance is favourable.

13. Do the COVID-19 vaccines not only keep the person from getting sick, but also from spreading the virus if exposed?

Ans: That is not yet known. As more data and monitoring are done, experts will be able to find out if a vaccinated person, if exposed to the virus, can still spread it even if they don't get the disease themselves.

14. Will it be possible to choose which vaccine you prefer?

Ans: In general, it does not matter, since once a vaccine gets the FDA's emergency use authorization (EUA), they all work. And even as more vaccines become authorized and available, you may have only one choice.

15. If a vaccine needs two doses, can you switch to another vaccine for the second one?

Ans: No. Experts advise staying with the same vaccine for both. That's true even for the Moderna and Pfizer vaccines, which use the same general approach yet are different.

16. How much of the population is likely to get vaccinated?

Ans: It's not possible to say, although surveys have cited a problem with “'vaccine hesitancy," even among health care workers. But that may change.

17. How much of the population needs to be vaccinated for so-called herd immunity?

Ans: Herd protection is not a goal of the initial rounds of vaccine deployment. "Only once population-wide vaccination is a reality would herd protection be even considered."

18. After I get vaccinated, do I still have to wear a mask?

Ans: Yes. Even after vaccination increases, say experts, preventive behaviours will still be needed. The ability to reduce transmission will require not just high vaccine uptake, but ongoing social distancing and masks, and herd protection may require high rates of vaccination in groups that are themselves at low risk.

19. Has the FDA approved a new vaccine?

Ans: Yes. The FDA granted emergency use authorization to the coronavirus vaccine from Janssen/Johnson & Johnson after reviewing its safety and efficacy data.

20. How many doses does the Johnson and Johnson vaccine require?

Ans: The Johnson & Johnson vaccine only requires one dose and can be stored at conventional refrigeration temperatures.

21. How effective is the Johnson and Johnson vaccine?

Ans: This vaccine is highly effective at preventing COVID, and even more effective at preventing severe COVID. It has also been shown to be effective against the B.1.351 strain that was first described in South Africa.

22. Does this vaccine work for people 60 years and older?

Ans: Documents the FDA released suggest a lower efficacy, 42%, for the Janssen/Johnson and Johnson immunization among people in this age group with certain relevant comorbidities. In contrast, without underlying conditions like heart disease or diabetes, efficacy in this cohort was 72%.

23. Is the COVID-19 vaccine beneficial for pregnant women and their babies?

Ans: Yes. One important reason to vaccinate pregnant women is so they can in turn provide their antibodies to the baby. This is known as passive immunity and it occurs when a mother is infected naturally or when she is vaccinated. The antibodies she produced are passed on to her baby through the placenta or via breast milk. This affords the baby protection against infectious diseases it might come in contact with while its own immune system is still maturing. It is one of the reasons, for example, that pregnant women in many countries, including the UK, are encouraged to be vaccinated for flu and whooping cough.