There are new headlines every day about the rapid development of vaccines to prevent COVID-19.In this Q&A, Gopi Patel, MD, Hospital Epidemiologist at The Mount Sinai Hospital, Medical Director for Antimicrobial Stewardship for the Mount Sinai Health System, and Associate Professor of Medicine (Infectious Diseases) at the Icahn School of Medicine at Mount Sinai, addresses some of the most pressing COVID-19 vaccine questions.
In general, how do vaccines work?
Vaccines expose us to pieces of either a bacterium or a virus, and our body mounts an immune response by making antibodies against those pieces. Antibodies are proteins that fight germs like viruses and bacteria by latching onto and disabling them. The goal is that our body will then recognize those pieces and use the antibodies to fight off any future exposure to the real bacteria or virus.
Can a COVID-19 vaccine give me COVID-19?
No. None of the vaccines in advanced clinical trials can give you COVID-19.
Gopi Patel, MD
Should I get a COVID-19 vaccine if I already have antibodies?
We are learning a lot more about the human response to COVID-19. A lot of people who have had COVID-19 did mount an antibody response, but we don’t know yet how long that response might last. So right now, if you have a history of COVID-19 it is still worthwhile to get a COVID-19 vaccine when they become available.
How will we know if a COVID-19 vaccine is safe?
The Food and Drug Administration (FDA), pharmaceutical companies, and scientists who are involved in vaccine development are all very committed to developing a safe and effective vaccine. There is rigorous testing for all vaccines to ensure safety. During any vaccine clinical trial, side effects or adverse events—health problems that happen after the vaccine is given, which may or may not have been caused by the vaccine—are recorded and monitored by safety monitoring boards before the vaccine becomes publicly available through either an Emergency Use Authorization or through FDA approval. All that data is made available and will be quite transparent. The goal is a safe and effective COVID-19 vaccine.
What if many people do not get a COVID-19 vaccine?
It is hard to say. Currently, the recommendation from the FDA is that if a COVID-19 vaccine is made available, it has to be at least 50 percent effective. That means when you test the vaccine in clinical trials, the group of people who got the vaccine has at least 50 percent fewer cases of COVID-19 than the “placebo” group who didn’t get the vaccine. I think there are lots of questions about how many individuals need to be vaccinated to reach what we call herd immunity, where the rate of immunity throughout a community makes the spread of a particular disease between individuals less likely.
What is herd immunity?
Herd immunity is the idea that you can protect vulnerable people if most of the population gets vaccinated and develops an immune response. We talked about this with something that hit New York hard in 2019, which was the measles. In the case of measles, when most people are vaccinated, that protects those individuals who cannot get vaccinated—the very young or those who have immune systems that can’t respond to the vaccine. So that’s the idea of herd immunity. It is very unclear at this point what herd immunity means for COVID-19. It may be that a lot of people may make antibodies, but we also have to make sure people don’t transmit infection. So practices like wearing masks, washing hands, and watching your distance are still really important, even in the setting of a vaccine.
How is Mount Sinai involved in the testing of a COVID-19 vaccine?
We’re very lucky at the Mount Sinai Health System in that we are actually involved in trials of COVID-19 vaccines. We’ve been involved in the trial of the Pfizer vaccine, one of the candidates that is furthest along in the process, and we’re starting enrollment in other trials soon. So we are prepared in terms of looking at the safety and efficacy of the four vaccines that are most advanced in Phase 3 clinical trials.
How is Mount Sinai planning for administering a vaccine once it becomes available?
Mount Sinai is already looking at how we would distribute and allocate a vaccine. It is important to remember that this vaccine would be administered under an Emergency Use Authorization from the FDA. So what would that look like? Who would we offer vaccination to, and how would we monitor those individuals? How would we make sure that we offer the vaccine to those who are most vulnerable to COVID-19 infection, whether it be in the community or in the health care setting? We know our health care workers are at risk. But we also know there are essential workers outside of health care who may be at risk. We’re working with our public health authorities—including the New York State Department of Health and our New York City Department of Health and Mental Hygiene—and watching the safety and efficacy data closely. Members of our Icahn School of Medicine at Mount Sinai faculty are working with New York State on the safety, efficacy, and evaluation of any vaccine candidate that becomes available in the next few months.