Recently as I browsed my Facebook feed, I noticed that some of my friends and family are uncomfortable about taking a COVID-19 vaccine. Although I am not an expert on vaccines per se, I realized that as a scientist I am more knowledgable about the topic than my friends who are not scientists or medical professionals. I posted that I would field questions about the vaccine. Here, I’ve curated and lightly edited some of the questions and my responses for public consumption.

Q: I watched a movie that freaked me out. How do we know that COVID-19 vaccines are not just scams?

One movie that made me suspicious of the pharmaceutical industry when I was younger was “The Fugitive” with Harrison Ford. However, after I learned of all the hoops that pharmaceutical companies have to jump through, how many drug candidates fail in clinical trials, and how there is post-market surveillance, I realized how unlikely the movie’s premise was. Hollywood sells drama!

You’re right that we don’t know what we don’t know. But to me, an organized conspiracy with many parts across many different companies and governments seems less likely than several independent vaccines actually being safe and similarly effective.

Q: How are these vaccines being made so quickly?

The clinical trials have been unusually quick because many steps which are typically sequential have been done at the same time. Usually they are sequential because if something fails in phase I there is no point of trying phase II or phase III. However the government poured money into running multiple phases at the same time so we can get a vaccine and get the pandemic under control more quickly.

A relative added “I work in oncology pharmacy, where most chemo drugs are approved on a fast track. Cancer patients just don’t have enough time to wait, especially for phase 3 when you need more than 10K patients enrolled. It’s not uncommon for a chemotherapy to be approved within 6 months to 1 year. That being said, FDA standards are very rigorous even within that short amount of time. With multiple vaccine candidates that have clinical trials with more than 15K patents enrolled, I would take it.”

Q: Will a COVID-19 vaccine change your genes?

Even if it contains genetic material or something similar, a vaccine will not change your genes any more than exposure to an actual virus. Your immune system contains cells that stick to things that are not normally part of your body. When it sees something unfamiliar, like part of a virus, it learns to stick to the unfamiliar particle more and more tightly over successive generations of cells.

Q: What is mRNA? How is an mRNA vaccine different from other vaccines?

mRNA is messenger RNA. It is a copy of DNA that is used by the ribosome. DNA is the genetic code that contains instructions for making proteins and the ribosome is factory that makes proteins. Viruses like SARS-CoV-2 hijack the cellular machinery to use host ribosomes to make new viruses.

mRNA vaccines are a new type of vaccine. Chemically, they are similar but not exactly the same as mRNA. If they were exactly the same, they would probably be cut up by the body before entering cells. The SARS-CoV-2 mRNA vaccines contain instructions for making the spike protein, a protein that appears on the surface of the virus. They do not contain instructions for making the whole virus, so they should be safe. When the ribosome makes a copy of the spike, your immune system learns to recognize it and fight against it if it encounters the real virus.

There are many possible ways to make a vaccine. The other vaccine candidates are weakened viruses or contain part of the Spike protein. Weakened viruses might not work well because the body might already be immune to them and they never establish themselves enough for the body to require new immunity. Vaccine designers may make the wrong part of the Spike, make it in a way that doesn’t look like the actual virus, or have trouble producing mass quantities.

In principle, mRNA vaccines can be made quickly for any virus because we just need to have a genetic sequence of the virus. It has become cheap and easy to get genetic sequences. This is probably why the mRNA vaccine candidates are ahead of the other vaccine candidates in getting FDA approval.

Q: Is the AstraZeneca COVID-19 vaccine based on an aborted fetus?

The vaccine does not contain cells from the fetus, but some research to test the vaccine was done on cells grown from the fetus.

Q: If someone had COVID-19, will they still need the vaccine?

Probably not. If somebody has recovered from COVID-19, the virus itself has trained the immune system. There have been cases where people have had COVID-19 twice, but it’s the exception rather than the rule.

However, this is speculation and should not be taken as medical advice. As a PhD, I’m the wrong kind of doctor. I’m pretty sure that the first clinical trials were for people who have not been infected by virus. Nobody can say anything definitively about taking the vaccine after having COVID-19 unless there are clinical trials testing the vaccine on people who have already been infected. There is a chance that a vaccine can cause a stronger immune response than the virus itself. For now, I would say that getting a vaccine is not a big priority for somebody who already had the disease.

Q: One thing I was curious about is the virus mutation rate and how that affects the strain used for the vaccine. I wonder if a a new version will have to be developed on a yearly basis.

Coronaviruses seem to mutate more slowly than influenza. Still, it is possible that COVID-19 will change and make the first vaccines less effective or that that immunity will wear off and we will need booster shots.

Q: How has cancer not been taken this seriously? This is essentially going to be eradicated or controlled in less than 2 years. Cancer research is ongoing.

Good question! Cancer is a very different beast than COVID-19.

In cancer, your own cells grow out of control and your immune system doesn’t know that they are bad. On the other hand, COVID-19 is caused by a virus and your immune system can learn that it is a foreign agent that should be eliminated. It just needs to trained by exposure to some part of the virus. That’s what all the COVID-19 vaccine candidates do.

Another difference between COVID-19 and cancer is that many different genetic events can cause cancer. Cancer is not really one disease but a group of diseases with similar symptoms. This means that a treatment may work for one person’s cancer but not another.

A random tidbit that sort of ties the two together is that much of the recent progress in cancer treatments are in immunotherapy, training the immune system to recognize cancerous cells as something to attack.

Q: What are your thoughts on the COVID-19 vaccine? What about vaccine usage in general?

I’m looking forward to the COVID-19 vaccines! I hope that they will play a key role in finally getting the pandemic under control.

With other vaccines, I trust the medical and regulatory system to only recommend those that have been found to be safe and effective and where the benefits outweigh the risks.