First, I am so excited to have a safe vaccination against Covid-19! This vaccine has excellent efficacy against clinical disease and almost 100% efficacy against serious disease. It is an incredible achievement and will help us get to herd immunity and some semblance of normal.

As with previous posts, to make it easiest to understand I’ll answer some common questions about the Pfizer vaccination that is now available.

This vaccine was developed so fast, how do you know it is safe?

Researchers have studied spike proteins in SARS and MERS extensively and developed experimental vaccines using mRNA. Because of this, they were able to fast track the development of a Covid-19 vaccine. They used the template for the SARS vaccine and swapped just enough genetic code to make it work for the new coronavirus, aka SARS-CoV-2.

mRNA has also been used in some treatments for cancer, studied in Zika, Ebola, and other viruses. Once we got the genome for Covid-19 in early 2020, scientists were able to “plug and play”.

Will the vaccine alter my DNA?

No. The mRNA that is part of the vaccine injected, tells your cells to make the spike protein on the outside of the cell that is recognized by your immune system to attack if exposed to covid-19. The mRNA is very delicate and degrades quickly (hence the need for storage at such cold temperatures). It’s not going to be able to stick around long enough to get into the nucleus of your cells where your DNA information is held.

Will I be shedding covid particles when I get vaccinated and possibly expose others that haven’t had the infection?

No. Some vaccines work by injecting “dead virus” like the flu shot. And one of our options for future vaccinations may be similar. But the Pfizer and Moderna vaccines do not inject any covid-19 virus at all into your body.

Can you get the vaccine if you’ve had Covid-19 infection?

Yes, because we don’t know how long immunity lasts of those that were infected, it is recommended to get the vaccine at least 30-90 days after a confirmed positive case.

Why would someone need to get the vaccine if they have already had covid-19? Won’t they already have immunity?

Not necessarily. Since we’ve seen cases of reinfection, we don’t know how long immunity lasts and have no way of telling how strong an immune response by each individual’s immune system is. The vaccine is more uniform so as long term studies are done, we’ll know more about how long its protection will be. Vaccines are usually more protective than a person’s natural immune response to a virus.

Will the vaccine affect fertility or cause me to become sterile?

Not likely. In the Pfizer study, 23 participants that got the vaccine verses placebo got pregnant when they weren’t supposed to (or by accident). The pregnancy outcomes were actually better in the vaccinated group than the placebo group.

What about other adverse reactions of the vaccine?

You can expect possible elevated temperatures, muscle aches, and soreness at the injection site up to 48 hours after getting the vaccine. The vaccine does not contain any preservatives like aluminum and thimerosal or egg products.

What about long term effects of the vaccine?

The vaccine is only in your body for a short period of time. Adverse effects are typically seen within hours or 3-6 months after injection. Remember this technology has been around and studied before covid-19, so we have a pretty good idea of the side effects. The trials will not stop just because of approval, and the long term effects will continue to be studied. All the effects will be monitored such as immunity (good outcome) as well as adverse effects (bad outcome).

How long will the vaccine last? Will we need to get boosters like the tetanus vaccine or yearly injections like the flu vaccine?

To be determined. The studies are ongoing to answer questions like these. The flu vaccine is only ~60% effective which is why we have to tweak it every year. The covid-19 vaccines out now have amazing efficacy after 2 injections- 95%!

Do I really need 2 injections? What happens if I only get the first dose?

Yes! You need both injections. The efficacy after the first dose was around 50% (for Pfizer’s) and hit 95% efficacy 14 days after the 2nd dose. If you take both doses, your 95% efficacy will hit 5 weeks after dose 1. We don’t have the confirmed data from Moderna but profiles are similar.

When can I get the vaccine?

The vaccine is only available to high risk healthcare workers, physicians, nurses, respiratory therapists, cleaning crew, etc. in the hospital setting currently. There is a planned phased release of vaccine to the general population based on risk factors and need.

What about my family member in the nursing home? When will those residents and staff get vaccinated?

They are part of the 1st phase of the Moderna vaccine to be administered in collaboration with CVS. The EUA (Emergency Use Authorization) of the Moderna vaccine is expected later this week.

Once vaccinated, will I be able to stop wearing a mask and social distancing?

Unfortunately, not yet. There is still a question of whether a vaccinated person can have asymptomatic infection which could then be transmitted to others. We do know that the vaccines prevent symptomatic disease and serious illness/death. The trials will be ongoing to be able to answer this.

When will we reach herd immunity and be able to open up?

Depends and hard to know. We need everyone that is eligible to get a vaccine to take it because we want enough people protected so that the virus can’t find a host and will die out. It may take up to 70% or so of the population vaccinated before this happens. We can speed this process up with the vaccine which is good news.

What age group has been studied and can get vaccinated?

People ages 16 and up have been studied. Since most 16-18 year old people will not be high risk, we have some time before deciding which phase they will be vaccinated in. For colleges to open safely, it may need to be along with other adults.

Is the vaccine safe in children?

Probably, but not studied yet. The studies have just opened up the trials to ages 12 and up. Once those are shown to be safe, then the studies will continue to test younger children. Hopefully, we can reach herd immunity with enough vaccinated adults before having to include children, but this is an unknown variable currently.

What is the best way to protect my children from getting infected if they aren’t getting vaccinated yet?

By having every adult around the children to be vaccinated, especially those in the same household. A virus needs a vector to infect (infected adult) and a host to spread (unvaccinated person). So the more vaccinated people around you there are, the safer you are.

There are more complicated issues around the vaccine such as people that are pregnant or immunocompromised. While I can tell you the data on this, it is probably a discussion better had with your doctor. I hope these questions and answers provide some clarity so that you can have some of the hope and excitement that many in the scientific community are experiencing. It really is such good news and a remarkable achievement. Until next time, be excellent to each other, wash your hands, and cover your face.