Quotes from Experts

COVID-19 vaccine boosters

SciLine reaches out to our network of scientific experts and poses commonly asked questions about newsworthy topics. Reporters can use the video clips, audio, and comments below in news stories, with attribution to the scientist who made them.

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October 15, 2021


What evidence should individuals weigh when deciding whether to get a booster dose of the Moderna vaccine?


“The data suggest that the booster will enhance protective antibody responses. This would likely improve the transmission-blocking component of vaccination, potentially increasing the window of time that an individual will be resistant to infection and subsequent transmission. However, for protection from severe disease, the current data suggest that the booster vaccine is likely not necessary and that we should be prioritizing vaccination of unvaccinated individuals over administration of third shots. ​However, certain individuals would likely benefit from a third dose, including the elderly, immunocompromised, and those at high risk for SARS-CoV-2 infection.”

Jesse Erasmus, Ph.D.
Acting assistant professor of Microbiology, University of Washington School of Medicine; director of virology, HDT Bio

“There is good data from the U.S. that shows the two-dose Moderna series continues to show strong protection against severe disease with the delta variant (93% protection against hospitalizations in a Centers for Disease Control and Prevention analysis performed in 18 states). The Moderna vaccine was also associated with a two-fold risk reduction in developing mild breakthrough cases in the Mayo Clinic compared to the Pfizer vaccine. The Moderna booster has only been recommended for selected groups (immunocompromised, 65 and older, those younger with medical conditions, and those in occupations with frequent exposure) and, given the continuing strong protection of the two-dose series in U.S. data, I think individuals should only consider this booster if immunocompromised or over 65, especially with other medical conditions.”

Monica Gandhi, M.D., M.P.H.
Infectious diseases doctor and professor of medicine, University of California, San Francisco

“Those who received the Moderna vaccine should be reassured that, regardless of whether or not they choose to receive a booster, as of now protection from severe disease, hospitalization, and death remains excellent. The big advantage of a booster dose in this group is that it will provide better, higher-level immunity that will not only provide added protection from severe disease, but also likely from being infected at all with the delta variant. In Israel, which has the most data on the real-world impact of third doses, the likelihood of becoming infected plummeted about two weeks after receiving a third dose. Many people, and I include myself in this group, would love to reduce their risk of getting infected as much as possible. Having a group of people who are at dramatically lower risk of becoming infected at all may also help act as a metaphorical firebreak, reducing the amount of virus in communities and reducing everyone’s risk of becoming infected.”

Dave O’Connor, Ph.D.
University of Wisconsin Medical Foundation Professor of Pathology and Laboratory Medicine, University of Wisconsin-Madison

We know that Moderna and Pfizer vaccines both continue to protect vaccinated individuals against severe disease, hospitalization, and death. Vaccine-generated immunity does wane with time, however, so the Food and Drug Administration advisers have recommended a booster strategy designed to extend protection for the following groups:

  • individuals 65 years of age and older;
  • individuals 18 through 64 years of age at high risk of severe COVID-19; and
  • individuals 18 through 64 years of age whose frequent institutional or occupational exposure to SARS-CoV-2 puts them at high risk of serious complications of COVID-19 including severe COVID-19.

This puts the Moderna booster on equal footing with the Pfizer booster. The committee evaluated the data available regarding waning immunity, including some data from Israel that suggests a booster can help reduce severe disease in elderly individuals. There remains some debate on the overall need for boosters. However, there is no doubt that the titers of neutralizing antibodies (a key measure of vaccine responses and potential indicator of protection) rise substantially following a third dose of either of the mRNA vaccines.

Paul Spearman, M.D.
Professor and director of infectious diseases, Cincinnati Children’s Hospital

What evidence should individuals weigh when deciding whether to get a booster dose of the Johnson & Johnson vaccine?


“In terms of the Johnson & Johnson ‘booster’ or second dose, the same comparison analysis from the CDC showed that the one-dose Johnson & Johnson vaccine provided only 71% protection against hospitalization during the delta surge. The FDA panel today essentially recommended the Johnson & Johnson vaccine as a two-dose series for everyone—not just in selected groups—with the second dose to be given two months after the first.”

Monica Gandhi, M.D., M.P.H.
Infectious diseases doctor and professor of medicine, University of California, San Francisco

“If a friend received the Johnson & Johnson vaccine, I would strongly urge them to get a booster. The convenience of this single-dose regimen was important earlier in the year, but the immunity it engendered isn’t as potent as the mRNA vaccines. As we head into the winter, getting a booster as soon as it is available to improve protection is like putting snow tires on a car; you don’t want to wait until there is a blizzard to start thinking about it.”

Dave O’Connor, Ph.D.
University of Wisconsin Medical Foundation Professor of Pathology and Laboratory Medicine, University of Wisconsin-Madison

It is important to remember the Johnson & Johnson vaccine continues to protect individuals against severe disease from COVID-19. The available data suggest that a second dose of the Johnson & Johnson vaccine does boost neutralizing antibody titers, although in a somewhat modest manner. The FDA review panel recommended that everyone who has received the Johnson & Johnson vaccine receive a second dose, with the idea that the second dose will increase protection levels, which were somewhat lower than that seen with the two-dose mRNA vaccines. Making this a more interesting question is a study called the Mix and Match Study, where mRNA or adenoviral vector boosters were compared. Although a small study, the available data suggest that it may be advantageous to pursue heterologous boosting (adenovirus followed by mRNA) as compared with homologous boosting (adenovirus followed by adenovirus). While this result does not negate the potential value of a second adenovirus dose, it may mean that heterologous boosting is considered in future meetings.

One concern raised by panel members and shared by others is that new recommendations for boosters could confuse the public. Individuals should note that changing recommendations are made in response to new data weighing the protective efficacy of our current vaccines and the higher boosted levels of antibodies, with the goal of providing the best protection for all Americans.

Paul Spearman, M.D.
Professor and director of infectious diseases, Cincinnati Children’s Hospital

For individuals who were initially vaccinated with the Johnson & Johnson vaccine, what does the evidence say about a follow-up booster shot of an mRNA vaccine?


“Considering recent studies in humans, looking at a single dose of the Johnson & Johnson vaccine followed by an mRNA booster, as well as plentiful studies in animal models that addressed heterologous prime/boost regimens with adenovirus-vectored vaccines and mRNA vaccines in the context of COVID-19 as well as other diseases, the data suggest that this type of regimen is extremely immunogenic and would very likely improve protective efficacy compared to a single dose of the Johnson & Johnson vaccine. One endpoint that was not addressed in the human studies that we and others have seen in animal models is that this heterologous prime/boost regimen (adenovirus followed by mRNA) significantly enhances T cell responses to levels that cannot be achieved by each vaccine alone. These T cell responses could play an important role in protection against variants of concern. Of course, this needs to be evaluated in humans, but given the consistency between animal model and human studies that evaluated antibody responses following this heterologous vaccination regimen, it’s very likely that enhancement of T cell responses would be observed in humans. In the event that heterologous boosters are not offered and a homologous booster for Johnson & Johnson vaccinated individuals is made available, the data suggest that this would likely provide a benefit, although a heterologous booster with mRNA would be ideal for reasons described above.”

Jesse Erasmus, Ph.D.
Acting assistant professor of Microbiology, University of Washington School of Medicine; director of virology, HDT Bio

“Three studies to date have already shown us that administering “mixed vaccines” (one mRNA vaccine and one DNA/adenovirus vector vaccine in either order)  increases the immune response over two shots of the same vaccine (one study in the UK, one in Spain and one in Germany).  The National Institutes of Health mix and match study shows us the same thing, at least in terms of an antibody response. The Johnson & Johnson vaccine followed 12 or more weeks later by an mRNA vaccine (either Moderna or Pfizer) leads to a higher antibody response (by more than ten-fold) than giving a Johnson & Johnson booster.  However, the second dose of a Johnson & Johnson vaccine, as reported by the company, does provide high vaccine effectiveness (94%) and a strong T cell and antibody response.  Given this mix-and-match study evidence, the Food and Drug Administration is likely to eventually approve an mRNA dose following an initial Johnson & Johnson vaccine dose.  At that point, those who got an initial Johnson & Johnson vaccination can either receive a second dose of Johnson & Johnson two months later or a second dose with an mRNA vaccine, either Moderna or Pfizer.  The FDA is likely to make the recommendation on this mRNA shot after a Johnson & Johnson vaccination at a later meeting, as the FDA meeting today did not yet make that determination.”

Monica Gandhi, M.D., M.P.H.
Infectious diseases doctor and professor of medicine, University of California, San Francisco

“Recent National Institutes of Health data shows that so-called ‘heterologous’ boosters elicit stronger immunity than a second Johnson & Johnson dose. There are caveats to this study, perhaps the most important being that it has a relatively small number of participants. This could mask safety risks that will only be apparent once many more people receive mRNA boosters. With that said, there is also a very real risk that suboptimal boosting could increase vulnerability to SARS-CoV-2 infection into the winter and beyond. Weighing these risks and benefits is inherently subjective, and reasonable scientists might disagree about the optimal balance. To me, a higher antibody titer that confers better protection from COVID would be worth accepting that there would be some unknowns that cannot become clear until later. If I were given the choice, I would prefer an mRNA booster. If that is not an option, a second Johnson & Johnson booster would be better than no booster at all.”

Dave O’Connor, Ph.D.
University of Wisconsin Medical Foundation Professor of Pathology and Laboratory Medicine, University of Wisconsin-Madison

September 30, 2021


The CDC advises that some groups such as those age 65+ “should” get boosters of the Pfizer-BioNTech vaccine. Others like health care workers and teachers “may” get a booster. What factors should those in the second group weigh when deciding whether to get a booster dose?


Camille Kotton, M.D.

“So at this point, frontline workers may get an additional dose of vaccine. The majority of those frontline workers are actually protected by robust vaccine immunity, at this point, and are unlikely to need an additional dose of vaccine. That being said, the new guidance from the CDC suggests that they can get an additional dose of vaccine. And for some, perhaps due to extenuating health circumstances of either their own or family members or whatnot, they may feel more comfortable getting an additional dose of vaccine which they could do at this point.” (Posted September 30, 2021 | Download Video)

Camille Kotton, M.D.
Clinical director of transplant and immunocompromised host infectious diseases, Infectious Diseases Division, Massachusetts General Hospital

Steven Varga, Ph.D.

“The COVID vaccines are working very well to prevent severe illness, hospitalization, and death. With the delta variant’s dominance as the circulating strain—and cases of COVID-19 increasing significantly across the U.S.—a booster dose will help strengthen protection against severe disease in those populations who are at high risk for exposure to COVID-19 or the complications from severe disease.” (Posted September 30, 2021 | Download Video)

Steven Varga, Ph.D.
Professor of microbiology and immunology, University of Iowa Carver College of Medicine

Can booster doses of the Pfizer-BioNTech vaccine be expected to slow the spread of COVID-19 infections? Or is the benefit purely a reduction in symptomatic disease?


Camille Kotton, M.D.

“The data show that an additional dose of vaccine decreases significant infections, and currently the majority of transmissions occur because of unvaccinated people. So we don’t know that an additional dose of vaccine will definitely decrease transmission, but we are cautiously optimistic that with overall lower disease rates in the community we will have lower rates of transmission.” (Posted September 30, 2021 | Download Video)

Camille Kotton, M.D.
Clinical director of transplant and immunocompromised host infectious diseases, Infectious Diseases Division, Massachusetts General Hospital

Steven Varga, Ph.D.

“Because not enough people have received the booster dose, we don’t yet have clear data regarding whether or not it will decrease the chances that a vaccinated individual could become infected or spread the virus. However, the data thus far show that individuals that received the booster exhibit an increase in their antibody response, which should result in increased immunity and should limit the chances that they would spread the virus to others. That increased immunity is certainly likely to decrease the frequency of people that have been vaccinated and experience symptomatic disease.” (Posted September 30, 2021 | Download Video)

Steven Varga, Ph.D.
Professor of microbiology and immunology, University of Iowa Carver College of Medicine

Boosters are available as soon as six months after the second dose. What does the evidence say about this timing versus a later booster dose?


Camille Kotton, M.D.

“The data look pretty convincing that for people over the age of sixty-five who have waning immunity, an additional dose of vaccine six months after they finish their primary Pfizer vaccine series would be a good idea. But, for the majority of other groups, it does not look as convincing that they need to go out starting exactly six months afterwards and they could delay a bit. Most people would still be very well protected by robust immunity from their primary vaccine series.” (Posted September 30, 2021 | Download Video)

Camille Kotton, M.D.
Clinical director of transplant and immunocompromised host infectious diseases, Infectious Diseases Division, Massachusetts General Hospital

Steven Varga, Ph.D.

“The data indicate that after two doses of the Pfizer-BioNTech vaccine, that individuals are very well protected from severe disease for at least six months after the second shot. However, similar to other vaccines such as the yearly influenza vaccine, immunity induced by COVID vaccines starts to wane after six months, which is why the booster shot has been recommended and approved by the FDA and CDC. Because immunity will continue to decline in most people over time, individuals that are at high risk for exposure, such as health care workers and teachers, should get the vaccine as close to six months after their second dose, rather than waiting longer which could result in an increased chance of an individual getting a breakthrough infection over time.” (Posted September 30, 2021 | Download Video)

Steven Varga, Ph.D.
Professor of microbiology and immunology, University of Iowa Carver College of Medicine

August 18, 2021


What does the evidence say about COVID-19 booster shots for everyone? What research questions about booster shots remain unanswered?


Dr. Jesse Goodman

“Right now, what’s driving this consideration of booster shots is two things: One, is we’re seeing the levels of antibody that vaccinated patients have decline over time, which can sometimes signal a loss in protection. But number two, more important, we’re seeing that the protection against overall infections is also declining. What we’re not seeing yet, and remain in question, is whether this has an effect on the outcomes we’re really trying to prevent, which is hospitalization, severe disease, death. And so far vaccine protection against those more severe manifestations is holding up well.”  (Posted August 18, 2021 | Download Video)

Jesse L. Goodman, M.D., M.P.H.
Professor of medicine, Georgetown University

Dr. Dorry Segev

“Eventually all of us will need booster shots for our COVID vaccines because the immune response we get to that vaccine decreases over time. This is called the durability of the immune response. We don’t know exactly how long the immune response will last, but we expect that at about eight months or so is when we’ll need that additional booster. Ongoing research will tell us better what that magic window is.” (Posted August 18, 2021 | Download Video)

Dorry Segev, M.D., Ph.D.
Professor of surgery and epidemiology, Johns Hopkins University

“The limited data sets shared by the vaccine manufacturers show that indeed a third shot substantially increases neutralizing serum antibody levels so the body can more effectively fight off the virus. However, these samples were collected within a month after that third shot, which would be the time antibody production is highest after a booster shot. Two main questions remain: First, how sustained is the increase in antibody levels? Ideally it would last six months or more. Second, would that third shot impact the spread of highly infectious variants, such as delta?” (Posted August 18, 2021)

Ali Ellebedy, Ph.D.
Associate professor, pathology & immunology, Washington University School of Medicine in St. Louis

“The term ‘booster’ shot implies that the primary vaccine series was effective at making a strong protective immune response, which has waned, and now needs to be revitalized.

“Evidence generally shows that the vaccines currently used in the United States remain strongly protective from severe illness, hospitalization and death, but that the mRNA vaccines may not be quite as effective as they were when first administered, especially for the delta variant. We’re seeing this in real-world data from the Pfizer and Moderna vaccine in New York, for example, as well as with the Pfizer vaccine in Israel. And although antibodies are not the only important part of immune protection, we are seeing decreasing antibody levels after full vaccination and less effectiveness of those antibodies against the delta variant. Data show that a booster dose will elevate immune responses significantly and should offer a substantially higher level of protection from infection and illness. These findings are most significant for those in the highest risk groups, including the elderly and those with high exposure, like health care workers and those in long-term care facilities. If boosters are recommended by the FDA and CDC, it is likely these groups will be targeted first.

“Data that are still coming out include comparable information for the Johnson & Johnson vaccine. We also would like to understand better how well previously vaccinated individuals are protected by their immune system’s ‘memory’ and T cell responses, which may kick in to provide protection from illness even if antibody levels have dropped.

“Finally, it is important to remember that this is highly dynamic, and decisions are being made with the best intentions to prevent as much illness as possible, even if complete and perfect data is not yet available. We have new information emerging continuously, paired with the current serious COVID-19 situation in United States and future changes in the virus that we cannot totally predict.” (Posted August 18, 2021)

Beth Kirkpatrick, M.D.
Professor, department of microbiology and molecular genetics, University of Vermont Larner College of Medicine

Toward the goal of ending the pandemic, what does the evidence show about boosting immunity for those already vaccinated versus prioritizing vaccine access worldwide?


Dr. Jesse Goodman

The most serious impacts of this pandemic are severe illness, hospitalization, stress on health systems, and all those consequences for patients and their families. To address that, we really need to focus first on vaccinating the unvaccinated, both here in the U.S. and globally. Booster shots may help protect some people, particularly our most vulnerable individuals, but are far less likely to impact the overall curve of the pandemic.” (Posted August 18, 2021 | Download Video)

Jesse L. Goodman, M.D., M.P.H.
Professor of medicine, Georgetown University

Dr. Dorry Segev

The only way to really deal with this virus is for every single person to be vaccinated effectively against the virus. Vaccinating effectively means boosters for people whose vaccine immunity has decreased, and it means first vaccinations all across the world. Balancing these is challenging but it’s important for us to focus on getting both of these goals accomplished.” (Posted August 18, 2021 | Download Video)

Dorry Segev, M.D., Ph.D.
Professor of surgery and epidemiology, Johns Hopkins University

“The virus flourishes in communities where vaccination rates are very low—that is where variants emerge.” (Posted August 18, 2021)

Ali Ellebedy, Ph.D.
Associate professor, pathology & immunology, Washington University School of Medicine in St. Louis

Worldwide equity in vaccine access is arguably the most important challenge we are facing in this pandemic. In addition to the enormous humanitarian issues in regions without vaccine access, the lack of vaccinations will permit the emergence of other new variants and will impede the global control of this pandemic. This makes booster shots in the United States a very challenging decision.  We must protect our own citizens, and at the same time show a similarly aggressive and steadfast commitment to get these vaccines to all populations throughout the globe.” (Posted August 18, 2021)

Beth Kirkpatrick, M.D.
Professor, department of microbiology and molecular genetics, University of Vermont Larner College of Medicine

Should we expect regular or annual COVID-19 booster shots?


Dr. Jesse Goodman

“We really don’t know yet how often we might need repeat COVID shots. Even though the antibody levels have been waning, suggesting we may need boosters periodically, we don’t know that they correlate perfectly with protection from infection. Also, we can’t predict what new variants COVID may throw at us and whether that may necessitate periodic changes and revaccination. So right now, anyone who tells you they can answer that question really can’t do so.” (Posted August 18, 2021 | Download Video)

Jesse L. Goodman, M.D., M.P.H.
Professor of medicine, Georgetown University

Dr. Dorry Segev

“I have little doubt that at least once a year we’re going to be getting boosters for this virus, either in the form of new vaccines that cover new variants or boosters that take our decreased immune response and help it regain some protection.” (Posted August 18, 2021 | Download Video)

Dorry Segev, M.D., Ph.D.
Professor of surgery and epidemiology, Johns Hopkins University

“That will largely depend on how the situation with the variants evolves. So far, I do not see a reason for a regular or annual shot.” (Posted August 18, 2021)

Ali Ellebedy, Ph.D.
Associate professor, pathology & immunology, Washington University School of Medicine in St. Louis

Might COVID-19 booster shot formulations change as the SARS-CoV-2 virus evolves?


Dr. Jesse Goodman

“The COVID virus has proved to be pretty tricky, and it sort of changes its coat constantly. And as we’re seeing now with delta sometimes these new variants may to some degree resist our vaccines. So I do think going forward we’re probably going to need to continually adapt our vaccines to changes in the virus, perhaps very much like we’re doing with influenza.” (Posted August 18, 2021 | Download Video)

Jesse L. Goodman, M.D., M.P.H.
Professor of medicine, Georgetown University

Dr. Dorry Segev

“Right now in terms of boosters what we have are the same vaccine over again. So if our immune system has decreased to the vaccine we got, we can give more vaccine and our immune response increases. Ultimately I think what will happen is the variants will change to the point where we need new formulations of the vaccine. And I expect that that will happen every one to two years where the booster will actually be a new vaccine formulation.” (Posted August 18, 2021 | Download Video)

Dorry Segev, M.D., Ph.D.
Professor of surgery and epidemiology, Johns Hopkins University

“Yes, this is a likely possibility. It will depend on how infectious new variants are and if the current vaccine can still prime our immune system to recognize them.” (Posted August 18, 2021)

Ali Ellebedy, Ph.D.
Associate professor, pathology & immunology, Washington University School of Medicine in St. Louis

Yes, this is certainly possible. Vaccine companies test whether antibodies made in the body following the original vaccine formulation will still work to neutralize new viral variants. If they do, the formulations will not change. If not, then we can expect vaccine formulations to be modified to optimize effectiveness.” (Posted August 18, 2021)

Beth Kirkpatrick, M.D.
Professor, department of microbiology and molecular genetics, University of Vermont Larner College of Medicine

August 13, 2021


What does the research show about the benefits of a COVID-19 vaccine booster for different groups of people?


“With the standard two-dose regimen of the mRNA vaccines, half of transplant patients don’t produce any detectable antibody response, and even those who do show some antibody response have, in general, lower levels of antibodies than the general population. In addition, clinical protection for vaccinated transplant patients is much lower: A fully vaccinated transplant patient has an 82-fold higher risk of getting a breakthrough infection, and a 485-fold higher risk of getting a breakthrough infection associated with hospitalization or death, than the general fully vaccinated public.

“Other immunosuppressed populations also have decreased responses to the vaccines, although the amount of the decrease varies by the medications they take and the condition they have.” (Posted August 13, 2021)

Dorry Segev, M.D. Ph.D.
Professor of surgery and epidemiology, director, Epidemiology Research Group in Organ Transplantation, Johns Hopkins University

“The proactive approach that the FDA is taking by authorizing booster vaccinations for the immune compromised is very welcome news. So far there have been somewhat limited data about booster shots—meaning an extra dose of the same or a different vaccine beyond the currently authorized vaccination schedule—but emerging evidence seems to suggest that they can strengthen or achieve immunity in patients who are immune suppressed and who generally have a lesser chance of mounting an immune response. This includes patients after a solid organ transplant, certain types of cancers, especially blood cancers, and certain types of cancer treatments that impair the immune system. The limited data in patients with solid organ transplants or certain cancer types, for example, might suggest that the booster shot converts 20-40% of patients from an antibody negative test to a positive one—meaning the patients have at least some detectable level of immunity by a lab test after their booster shot. In addition, booster shots in these studies have been overall just as safe as vaccinations otherwise. Questions remain about whether booster shots work for all patients or if some patients have such a low chance to respond to the additional shots that they need other methods of protection, as well as whether a mix and match strategy might work better—meaning getting a different type of a booster vaccine than the original series.” (Posted August 13, 2021)

Balazs Halmos, M.D.
Professor of medicine, Montefiore Medical Center/Albert Einstein College of Medicine

Our study shows that in organ transplant recipients, a third dose of the Moderna mRNA vaccine was significantly better than a placebo for improving patients’ immune response. Organ transplant patients have a very poor response to the standard two dose regimen of COVID-19 vaccines. With a third dose, as compared to placebo, patients in our study had increased antibodies against the spike protein, as well as neutralizing antibodies, which serve to prevent viral infection, and T-cell responses, which limit severity of infection. Ours is the first study to include a placebo group for comparison with the group receiving a booster shot, which is very important to demonstrate the efficacy of an intervention. Based on the results of this study, we believe that a third dose should be recommended for organ transplant patients. The results may also be applicable to other groups of immunocompromised patients such as cancer chemotherapy or bone marrow transplant recipients, but we encourage further studies in those groups.” (Posted August 13, 2021)

Atul Humar, M.D.
Director of transplantation, University Health Network, Toronto

How do policymakers decide who is eligible to receive a COVID-19 booster shot?


“With the phrasing of the FDA authorization, it seems that this will be an individual decision between a patient and their medical team, balancing the risk of the third dose, such as risk of rejection in organ transplant patients, versus the benefits. It is also possible to use antibody levels as a surrogate for how much immune protection the patient had, and to include the results of these tests as part of the clinical decision-making.” (Posted August 13, 2021)

Dorry Segev, M.D. Ph.D.
Professor of surgery and epidemiology, director, Epidemiology Research Group in Organ Transplantation, Johns Hopkins University

“There is evidence emerging that immunity after vaccinations might wane slightly over time and also that some patient groups might just not develop immunity from the usual vaccine doses. Because of this, there is a lot of interest in boosters for both certain patient cohorts, such as immune suppressed patients with an organ transplant or on cancer therapy, as well as the larger community—in particular, more vulnerable members, such as the very elderly. Next there will be discussions about boosters for health care workers because they have the highest risk of exposures working at front lines and then, finally, the general population. All these decisions should keep in mind health equity issues among populations within the U.S. as well as globally, as some countries have had very little access to vaccines, let alone boosters. Accordingly, our first consideration needs to be identifying populations at the highest risk from COVID-19 who might not be protected by the standard vaccinations—immune suppressed patients and possibly the elderly in the next wave.” (Posted August 13, 2021)

Balazs Halmos, M.D.
Professor of medicine, Montefiore Medical Center/Albert Einstein College of Medicine

“They generally review available evidence and decide. We have shared our data with the FDA and other regulatory authorities. The best type of evidence is usually considered a randomized controlled trial.” (Posted August 13, 2021)

Atul Humar, M.D.
Director of transplantation, University Health Network, Toronto

How do doctors decide which patients need a COVID-19 booster shot?


“Doctors will need to follow FDA and CDC guidance and then discuss with their patients the pros and cons of booster vaccinations dependent on each patient’s overall risk/benefit assessment as to their underlying disease and ongoing therapy with regards to immune suppression. Booster shots will likely be an excellent suggestion for a patient following an organ transplant who is on chronic immune suppression, but it is less clear if booster shots are helpful for a patient with a remote history of cancer without any ongoing therapy that could lead to immune suppression.” (Posted August 13, 2021)

Balazs Halmos, M.D.
Professor of medicine, Montefiore Medical Center/Albert Einstein College of Medicine

Creative Commons LicenseThe text and video on this page are licensed as Creative Commons CC BY-SA 4.0. Journalists are free to use any text or video on this page with or without attribution to SciLine.

Ali Ellebedy, Ph.D., associate professor, pathology & immunology, Washington University School of Medicine in St. Louis

None.

Jesse Erasmus, Ph.D., acting assistant professor of Microbiology, University of Washington School of Medicine; director of virology, HDT Bio

Dr. Erasmus is employed by and has equity interest in HDT Bio, a company actively developing vaccines and therapeutics for cancer and infectious diseases, including COVID-19.

Monica Gandhi, M.D., M.P.H., infectious diseases doctor and professor of medicine, University of California, San Francisco

None.

Jesse L. Goodman, M.D., M.P.H., professor of medicine, Georgetown University

Dr. Goodman is an infectious diseases clinician and also conducts research and policy work on emerging infectious diseases. He was previously FDA chief scientist, and before that director of FDA’s Center for Biologics Evaluation and Research (CBER). He reports serving as a board member for GSK and for Intellia Therapeutics (for which he receives compensation), and as a board member for the US Pharmacopeia, and on the scientific advisory board for the International AIDS Vaccine Initiative (IAVI) (both volunteer positions).

Balazs Halmos, M.D., professor of medicine, Montefiore Medical Center/Albert Einstein College of Medicine

None.

Atul Humar, M.D., director of transplantation, University Health Network, Toronto

No relevant disclosures to this work. Specifically, the study received no funding or involvement from Moderna.

Camille Kotton, M.D., clinical director of transplant and immunocompromised host infectious diseases, Infectious Diseases Division, Massachusetts General Hospital

Dr. Kotton has been involved with BeiGene in clinical trial adjudication (monoclonal antibody), and a site investigator (zanubrutinib). She is a voting member of the CDC Advisory Committee on Immunization Practices.

Dave O’Connor, Ph.D., University of Wisconsin Medical Foundation Professor of Pathology and Laboratory Medicine, University of Wisconsin-Madison

I am not directly involved in any of the COVID-19 vaccine trials; however, I have received grant funding from Bristol Myers Squibb and Amgen and have done collaborative genetics work with many pharmaceutical companies including Pfizer. I am a participant in the AstraZeneca phase III vaccine trial.

Paul Offit, M.D., professor of vaccinology and pediatrics, Perelman School of Medicine at the University of Pennsylvania, director of the Vaccine Education Center at Children’s Hospital of Philadelphia (CHOP)

None

Dorry Segev, M.D. Ph.D., professor of surgery and epidemiology, director, Epidemiology Research Group in Organ Transplantation, Johns Hopkins University

I am the PI of an NIH-funded trial of booster doses in transplant patients that just launched this week.

Paul Spearman, M.D., professor and director of infectious diseases, Cincinnati Children’s Hospital

I hold NIH grants (NIH is involved in many current vaccine efforts). I am a member of the Leadership Group of the Infectious Diseases Clinical Research Consortium, which evaluates some COVID-related proposals. My division is conducting trials with the Pfizer and AstraZeneca COVID19 vaccines. I am a member of the Vaccines and Related Biological Products Advisory Committee (VRBPAC) of the FDA. My views are my own and do not represent those of the FDA.

Steven Varga, Ph.D., professor of microbiology and immunology, University of Iowa Carver College of Medicine

Dr. Varga is an immunologist who is developing vaccines against respiratory syncytial virus (RSV) as well as other respiratory viruses. No funding for these activities has been received from for-profit entities.