Judith A. Aberg, MD
Several worrisome new variants of SARS-CoV-2, the virus that causes COVID-19, have been detected within the United States since the COVID-19 vaccine rollout began in December, raising concerns about the nation’s ability to return to normal in 2021. Chief among these concerns is whether the national effort to vaccinate as many Americans as possible—and as quickly as possible—will be able to offset the virus’s enhanced ability to spread. At the heart of that question lies another: Will the authorized vaccines from Moderna, Inc., Pfizer/BioNTech, and Johnson & Johnson offer adequate protection against these new variants?
To answer these questions and more, Mount Sinai Today recently turned to Judith A. Aberg, MD, Dean of System Operations for Clinical Sciences, and Chief of the Division of Infectious Diseases, at the Icahn School of Medicine at Mount Sinai. Dr. Aberg, the Dr. George Baehr Professor of Clinical Medicine, leads the Mount Sinai Health System’s COVID-19 treatment and vaccine clinical trial efforts.
“We have to be clear that we are in unknown territory,” she says. “Every day we are learning something new. Individuals must have a realistic view of the immediate future and continue doing what we know works best: get vaccinated, wear masks, and practice social distancing—even after they are fully vaccinated.”
Do the vaccines from Moderna and Pfizer/BioNTech protect us from the new variants?
Dr. Aberg: At this time no one has sufficient data to really provide us with a definitive answer. We have indications from both Moderna and Pfizer/BioNTech that their vaccines produce enough effective antibodies to overcome the variants, but people may still become mildly ill from the variants although not severely ill. Both companies have also mentioned they are looking into making modifications to their vaccines, so there is the likelihood we will see them introduce booster shots in the coming months that may be more effective against new variants.
How effective is the Johnson & Johnson (J&J) vaccine that was just authorized by the Food and Drug Administration?
Dr. Aberg: I am very encouraged about the J&J vaccine, which is a single dose. We ran clinical trials at two of our hospitals, Mount Sinai Queens and Mount Sinai Brooklyn. In the United States, J&J found the vaccine was 72 percent effective. When they tested it in Brazil and South Africa—where new variants are widely circulating—the company found there were no deaths and it prevented people from developing severe disease. J&J is also looking into creating a booster dose and I imagine it will be very beneficial.
Will these variants prevent us from beating this pandemic?
Dr. Aberg: I suspect there are going to be more variants and we’re going to have to deal with them. Viruses want to live and they keep reproducing and mutating—whether it’s the human immunodeficiency virus (HIV), which causes AIDS, or the influenza virus, which develops different strains. Each year when I get the flu vaccine I hope that I won’t get the flu. There is still a chance, but the flu vaccine probably prevents me from developing a severe case.
With SARS-CoV-2, which causes COVID-19, you have variants. And until we have more data on vaccine durability and efficacy against the variants we’re going to have to do what we’re doing now. Vaccinated individuals should still follow safe practices but can feel some reassurance. And for those who aren’t yet vaccinated, don’t delay in getting whichever vaccine becomes available to you.
Is it okay to mix vaccines for the first and second doses or take more than one vaccine?
Dr. Aberg: Do not mix vaccines. Finish two doses of the same vaccine or, for Johnson & Johnson, take only the single dose. We do not know if the antibody response you get to one vaccine will impair your immune response to the other vaccine. Each vaccine, even Moderna’s and Pfizer/BioNTech’s, which are based on the same mRNA technology, is different enough.
Should vaccinated individuals test their antibody levels to make sure they are protected?
Dr. Aberg: No, we do not advise this. It is not informative. First, the vast majority of commercial antibody tests do not measure the antibodies you get from vaccines—they measure the antibodies you get from having COVID-19. These commercial serology results are not designed to detect immune response to the vaccine. There are tests that look for antibodies against the N protein or nucleocapsid. This is not coded for by the vaccine and will only inform about prior infection—nothing about your response to the vaccine. Second, the vaccine manufacturers have not reported what the antibody levels should be if you were to get a test that detects the S protein or spike, which is what the vaccines make antibodies against. We only know that people who were vaccinated had tremendous efficacy against getting COVID-19, and it may be irrespective of what their antibody levels are. There is more to immunity than just antibody production.
Do you recommend COVID-19 vaccinations for individuals who are immune-compromised?
Dr. Aberg: We do not have enough data to tell patients with compromised immune systems or who are on chemotherapies whether or not the vaccines are going to be effective for them. We are not saying they shouldn’t get vaccinated, we just don’t have enough data to determine how much protection they would receive. At Mount Sinai, we are involved in clinical testing of a hyperimmune globulin therapy—a purified, highly concentrated product of antibodies derived from antibody-rich plasma of people who have been infected by COVID-19 and recovered—which may benefit this population whose immune systems are impaired and cannot produce antibodies.
What is your advice for individuals who have been fully vaccinated?
Dr. Aberg: These vaccines are a very important part of our prevention toolbox. We cannot rely on just one thing. We don’t want to set expectations that you’re not going to get COVID-19, but the vaccines decrease your chances of getting really sick or being hospitalized. So until the virus is under better control and we do not see such a high incidence anymore, we still need to be careful. Don’t engage in magical thinking. I hear people say, “Now that I’m vaccinated I can go and do this and that.” And I say, “No, not really.” Everything in moderation.