COVID-19 Vaccine Questions & Answers

I have been getting quite a few questions about the COVID vaccine lately.  I understand that many people are hesitant to get the vaccine for various reasons.  There is a lot of false information about the vaccine in some media outlets and on the Internet, so I thought it might help to share some answers to common questions.

How can the vaccine be safe if it was developed so quickly for a virus that was so new in origin?

There are two parts to this question.  The first part is regarding the novel (or new) coronavirus.  Although this particular coronavirus, which causes COVID-19 (called SARS-CoV2) is a new virus, we have studied a number of coronaviruses over many years.  Prior to the emergence of SARS-CoV2, we knew of seven coronaviruses that could infect humans, and many others that infect other animals.  Two of those seven prior coronaviruses caused severe, often deadly, disease in humans.  The first was the initial SARS virus, SARS-CoV, which emerged in 2002 and caused severe disease outbreak in many countries through 2004.  The second was MERS-CoV, which emerged in 2012 and caused severe outbreak in middle eastern countries initially.  We still see some cases of this virus infection.

Now to how quickly the vaccine was developed.

Because so much research has been done on these prior coronaviruses, we already knew which protein from the virus was most likely to cause an immune response.  The process of figuring out which protein or piece of a virus to use in a vaccine to get an adequate immune response can sometimes take years.  We already knew this from extensive research on these prior coronaviruses, so that saved years right there.

Most people don't realize this, but the messenger RNA vaccine technology has been developed and perfected over almost 40 years, with the initial work starting in the mid-1980s.  A lot of kinks have been worked out throughout those years.  With this technology as it stands today, all you need know is which  protein to use and vaccine production can start, then the clinical trials can be done very soon after.

The combination of years of prior research in both of these areas allowed this vaccine to be developed rapidly.

Do fully vaccinated adults need a booster shot?

This week, the FDA approved, and the CDC has now recommended booster doses of the Pfizer vaccine.  The recommendation says that a booster should be offered to people 65 and older, nursing home residents, frontline workers, and certain adult who have risky underlying health problems.  The extra dose would be given once they are at least six months past their last Pfizer shot.

Data from Israel, where nearly 3 million people have already received a third Pfizer dose, has uncovered no serious health risks.

If we need a booster dose, does that mean the vaccines aren't working?

No.  COVID-19 vaccines are working very well to prevent severe illness, hospitalization, and death from COVID-19, even against the more severe Delta variant.  CDC data shows the vaccines still offer strong protection for all ages, but there is a slight drop in protection among older adults after 6 months.  The booster shot helps vaccinated people maintain protection for a longer period of time.

What is the difference between a booster dose and an additional dose?

The US has already authorized third doses of both the Pfizer and Moderna vaccines for certain people with weakened immune systems, such as cancer patients and transplant recipients.  This third dose is given at least 28 days after the second dose.  This is recommended because people who are immunocompromised may not develop enough protection from the usual 2 dose regimen.  Because this third dose is necessary for them to build up their initial immunity, it is not considered a booster.

We will continue with more questions and answers about the COVID vaccines next week.

If you have any questions about COVID-19 vaccines, please log into your account and send us your question. We are here to help.

Dr. Anita Bennett MD - Health Tip Content Editor