Mt Sinai

Q&A

How Effective are the Vaccines? A Mount Sinai Expert Weighs In

  • December 10th 2020

Only ten months after the first case of COVID-19 was identified in the United States, pharmaceutical companies are announcing promising vaccine trial results. This rapid progress could not have been possible without scientists generating insights about the virus. One of those scientists is Florian Krammer, professor of vaccinology at the Icahn School of Medicine at Mount Sinai, who has been researching how the virus attacks the body and is himself a vaccine trial participant. He and Ken Davis, President and CEO of the Mount Sinai Health System shed light on the progress and answer reader questions about vaccine effectiveness and the prospects for immunity.

Ken Davis What’s your reaction to news that vaccine candidates are showing strong efficacy?

Florian Krammer This is very good news. We have vaccine candidates that have efficacy at a time point when antibodies in the people vaccinated will still increase, so the response may still improve. We don’t yet know how well the vaccine works in the elderly, but this is a great step in the right direction. It also suggests other vaccines that are far along in development will have similar efficacy. It’s good news for all vaccines in development.

Davis Are you encouraged enough to expect vaccines will enable us to overcome COVID-19 in the coming year?

Krammer I’m very optimistic. This is the beginning of the end for COVID-19. But we have to be patient. The FDA has to decide if it wants to license it and how they want to license it. It’s likely that, in the next few months, the vaccine will be used in the population. However, it is important to clarify that having a vaccine doesn’t change things overnight. It will take some time until we see a de-escalation of the situation.
We need to first vaccinate people who are at higher risk and then a good portion of the general population. That’ll be the solution to the problem. It might take until late spring to make serious progress. It’s also reasonable to assume there will be less virus when it gets warmer and that might de-escalate the situation further.

Davis How bad could the situation get this winter?

Krammer: Bad. On many days we are now surpassing 2,000 deaths a day in the U.S. and case counts per day are still very high. We are basically back to the numbers we were seeing during the deadly spring wave and if this continues without effective countermeasures, it might even exceed the death toll we had in spring.
In Europe, we already see a strong surge in cases. The virus seems to like colder weather. Europe is ahead of the U.S., but we have a growing problem in the U.S. as well. We need to keep virus circulation down as much as possible until a vaccine becomes widely available. Cases are surging now and that’s really a problem.

Davis Do you expect there will be several effective vaccines?

Krammer Yes, and that’s important because there is no way Pfizer and Moderna can supply enough vaccine to meet the global demand. We need multiple vaccines to do that. It’s very likely that a larger number of vaccine candidates will show efficacy. In my mind there’s little doubt about that and we will likely have multiple vaccines in 2021.

Davis The COVID-19 vaccines have been developed in record time. Can you put that in perspective?

Krammer Usually, it takes 15 years to develop a new vaccine. Now this was done in about a year, 15 times faster than usual. However, it is important to emphasize that no shortcuts were taken in terms of safety and testing of the vaccines. But there was a lot of financial risk taken to speed things up. Availability of funding and financial de-risking are major factors that slow down vaccine development. But now, nobody cared about how much it costs. A lot of money was put into this and that’s why the vaccines were developed so quickly.

Davis What does this mean for future discovery of other vaccines?

Krammer Knowledge gained from testing different vaccine platforms in parallel might open pathways we haven’t considered before. But we’re not going to develop the next “normal” vaccine in a year — I don’t see that happening. Also, COVID-19 vaccines seem to be pretty straightforward. We knew this vaccine had to target the spike protein because antibodies that attach to that protein neutralize the virus. So, it’s not like designing and making an HIV or tuberculosis or malaria vaccine where there’s lots of trial and error and where everything is very complicated due to the nature of the pathogen.

Davis How long will the vaccine protect those who are vaccinated?

Krammer How long the antibodies will stay is a difficult question. It could be a year. It could be three years. It could be ten years. It’s not a big problem if the protection is only lasting for example three years, because at any time you can be revaccinated. We’ll have to monitor antibody levels to see if people need to be revaccinated and how often. This will be studied in phase four, post-marketing studies.

Davis How well does the antibody protect people?

Krammer We’re currently conducting studies to determine this. We enrolled people who had an infection and now have antibodies and people who don’t. We follow them and measure how the antibody level behaves over time. And we look at protection afforded by comparing COVID-19 cases in the antibody and the no-antibody group. This allows us to study how strong protection is and how much antibody you’ll have to have to be protected.

Davis Would it be safe for a senior citizen who is one of the early recipients of the vaccine to 

Krammer The efficacy of the vaccines from Pfizer and Moderna is in the 95 percent range for prevention of disease. If there is a lot of virus circulating in the population, as there is now in many U.S. states, there is still a risk since the vaccine is not 100 percent protective. I would certainly recommend postponing nonessential travel as long as the virus prevalence is that high and to still wear a mask if travel is really necessary since seniors are in a very high-risk group. However, if the virus prevalence were to drop there should be no issues in traveling.

Davis Can you discuss Mount Sinai’s response to COVID-19 and its role in the development of a vaccine?

Krammer I’m very proud of how Mount Sinai reacted. I think the response was phenomenal. Everyone stepped up their game and started to collaborate. And we had great leadership.
We were one of the first in the country to characterize the antibody response to the virus which was important for vaccine development. We investigated how antibodies might neutralize the virus, how long antibodies last and we determined the dynamics of the antibody response. And we worked on vaccine candidates and animal models to evaluate vaccines and therapeutics. And that’s just the small part of Mount Sinai’s efforts I was involved in. There are so many at Mount Sinai who contributed to understanding this new infection in so many aspects.
It’s very important on the clinical side to get involved in vaccine testing. Mount Sinai enrolled many individuals in the Pfizer vaccine trial and is now starting similar work with the Johnson and Johnson vaccine trial. Many of us also contributed personally and enrolled into trials. I’m one of the participants in the Pfizer vaccine trial and just got the second shot this morning. I think that is important too because it signals that we, as scientists and health care workers, believe in these vaccines.


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