Deciding Whether to Receive the COVID-19 Vaccine — and Which One — As More Are Authorized for Emergency Use by the FDA


With the second COVID-19 vaccine receiving emergency use authorization by the FDA, patients with cancer undergoing treatment should keep in mind how it may affect their therapy and the potential difference between the two vaccines by Pfizer-BioNTech and Moderna.

Since the Food and Drug Administration (FDA) has granted emergency use authorization for two COVID-19 vaccines, one by Pfizer-BioNTech and one by Moderna, many patients with cancer now have to take into consideration whether to get the vaccine and how it may affect their treatment.

Despite patients potentially feeling conflicted about which of the two vaccines to get, most patients receiving cancer treatment may have peace of mind knowing that either formulation should not affect most treatments. For example, patients undergoing surgery or radiation therapy for most cancers can be treated like the rest of the population, whereas those undergoing chemotherapy should have a discussion with their health care provider before making a decision.

CURE® spoke with Dr. Tian Zhang, assistant professor of medicine at Duke University School of Medicine and member of the Duke Cancer Institute, to learn more about what patients should keep in mind when making this decision and the implications that the vaccine may have in patients with and without cancer.

CURE®: What is the emergency use authorization of the COVID-19 vaccine mean for patients with cancer?

Zhang: Just as a preliminary disclaimer, I am a medical oncologist interpreting the vaccine data for my patients with cancer to the best of our current understanding of how the vaccine works and how our cancer therapies work.

But I do think that this emergency use authorization is truly a step forward in the COVID-19 pandemic, and a breakthrough for modern science that we've been able to generate and clinically test the COVID-19 vaccine over just about a year since the first reports of the initial infections. And, you know, the technology for these mRNA vaccines has been around and available for at least about the last 10 years. And the target spike protein of the SARS-CoV-2 virus was the perfect antigen to develop using the available technology.

So patients with cancer already have a preexisting condition. And in many large subsets of patients, we've seen more severe COVID-19 infections or higher mortality rates in patients who have cancer and develop COVID-19. Therefore, to me, the approval of the vaccine and the ability to potentially prevent COVID-19 infection is truly paramount to keeping our patients with cancer safe. And although the vaccine trials do not specifically include patients with cancer, I do think that the majority of patients with cancer will have similar immune responses to hopefully develop protective immunity against the SARS-CoV-2 virus.

Should all patients with cancer receive the vaccine or only certain cancer types?

I think that's a really good question. Patients who have had definitive surgery or radiation for localized cancers are probably the most similar to the normal population, and those patients should definitely undergo vaccination.

Patients who are receiving systemic treatments —and these are for patients who often will have cancer that has spread to a different organ. These patients may depend slightly on the nature of the systemic treatment. … Targeted treatments with small molecule inhibitors as well as our immune checkpoint inhibitors are probably fine and shouldn't impact the protective immune response from the vaccines.

Chemotherapy, that's truly cytotoxic. What we generally mean when we say chemotherapy (that it) is generally more immune suppressive, but not specifically suppressive of lymphocytes. Those are the B and T cells that are necessary for protective immune response from a vaccine. And so those patients undergoing chemotherapy should probably have a discussion with their oncologist about the better timing during a chemo cycle to receive the vaccine for the more optimal immune response.

And the main question then comes for patients who have a B cell lymphoma or plasma cell multiple myeloma, where their systemic treatments are truly suppressing those lymphocyte populations that are specifically necessary to generate an immune response. And so those patients, I think, the data (are) less clear about whether and how they will be able to generate an immune response to the COVID-19 vaccine. And, when in doubt, I think patients should ask their treating oncologist about whether it's safe and the right timing of the vaccine for them.

You mentioned patients who would be suitable for the vaccine and the patients who should discuss it with their physicians before proceeding, but are there any patients who you think would not be a good candidate for this vaccine whatsoever?

The FDA label of the vaccine does specifically say patients who have had anaphylactic reactions to prior vaccinations as well as to any components of the vaccine. And so that's listed quite clearly in the FDA label as the mRNA, lipids, potassium chloride and sodium chloride, or basically salt, potassium phosphate and sodium phosphate as well as sucrose. So if there are patients who have had prior truly anaphylactic reactions, they should probably be either carefully monitored during vaccination and the timeframe after, or they could opt to not receive it for the for the time being while we await more data.

Do you think this emergency use authorization from the FDA will allow patients to come back into the office for oncology appointments once again? And if so, when?

You know, our in-person visits have been ebbing and flowing basically depending on the incidence of COVID-19 in a certain geographic area. So I think that answer kind of depends on where people are practicing. But in general, I think when oncologists and nurses in the outpatient centers have been vaccinated, that will provide a safer environment for everyone coming in and out of the cancer center. And that safe environment will be even further enhanced when patients are also vaccinated. So, you know, from best estimates, I would hope that this would happen in the next three to six months.

So let's focus now on the blog post that you wrote for the Kidney Cancer Association, where you mentioned that patients with kidney cancer undergoing targeted treatments or immunotherapy may still be candidates for the vaccine. Do you mind going into more detail about that?

Patients with kidney cancer in our frontline settings are often getting what we call anti-VEGF (vascular endothelial growth factor) targeted treatments that are targeted against angiogenesis (forming new blood vessels from preexisting vessels), what I commonly term blood vessel blockers for our patients. Those patients probably should not have any immune-suppressive effects of their treatments. And so their response to the COVID-19 vaccine will likely be almost as good. You know, we don't have direct data to say, but based on best estimates, these patients may have a good response to generate a protective immunity against COVID-19.

For patients who are on immunotherapies for kidney cancer, these immunotherapies are generally checkpoint inhibitors, so either CTLA4 or PD-1/PD-L1 blockade. And, again, for these situations, this is more to activate the T cell response against tumor. And that should not, in and of itself, directly impact generating protective immunity from a B cell and T cell response from these vaccines. So in general, for patients who have kidney cancer who are on these targeted and immunotherapies, these should not impact their immune response to COVID-19 vaccine.

There are some non-clear cell, so more rare kidney cancers, that are treated with chemotherapies and cytotoxic chemotherapies. And so for those patients, I think there should be a discussion about when during a chemotherapy site goal would be best and optimal for a patient to have a protective immunity response against the vaccine.

If the patient is currently undergoing cancer treatment and are concerned about the vaccine potentially negatively impacting the treatment that they're receiving, what advice would you give them?

With the possibility of severe COVID infections and possible dying from COVID in our patients with cancer and preexisting conditions, I would think that the benefit of receiving the vaccine outweighs the risk. And so in thinking about the Pfizer vaccine data, there was about a 94% vaccine efficacy compared to the placebo. And so certainly, that protection that the vaccine potentially has outweighs the risk of the side effects. To generate a good protective immunity response that protects patients from COVID-19 is probably not inconsistent. So I don't think it's mutually exclusive of cancer-targeting treatments. We can specifically talk some more about patients with lymphomas or multiple myeloma where their cancer-targeting treatments are specifically inhibiting those B cell populations. But in most cases of solid tumors especially, the vaccine response should not change how they respond from the anti-cancer treatment.

So let's jump back to all patients with cancer regardless of the type. What advice would you give patients with cancer who are on the fence about whether to receive the vaccine or to hold off?

Sure, and this is where I think patients with cancer are a particularly vulnerable population because they already have a preexisting condition. Depending on where their cancer is, it might impact their lungs or their ability to really combat the virus, and patients who develop severe pneumonias may have more severe courses based on their prior malignancy. And so, you know, I do think that it may be a case-by-case, individual decision, but in most cases, the benefit of receiving a vaccine to prevent potentially severe COVID infections or possible death, you know, I do think that outweighs the risks of the vaccine itself.

Are there any other negative effects, potential drug-drug interactions or even other adverse effects with the vaccine that would specifically affect patients with cancer or that oncologists should be prepared for?

You know, I thought very hard about this question. And, you know, the only ones that I can potentially think about — and it's somewhat hypothetical — is that patients who are undergoing treatment targeted against B cell lymphomas or multiple myeloma plasma cells, those patients may or may not amount the right immune response to the COVID-19 vaccine. So, those are small, but a significant population where, you know, further discussion with their oncologist should determine if and when they should receive it.

As more vaccines receive this emergency use authorization or are approved by the FDA, how can patients decide which vaccine will be best for them, whether it be the Pfizer vaccine, the Moderna vaccine and potentially whichever ones come after that?

There's a beautiful review in Nature about these vaccines, but about 140 preclinical studies of vaccines, 20 vaccines that are currently in phase 1, about a dozen in phase 1-2 and about 10 and phase 3 trials. And as of today, December 16, the Pfizer/BioNTech vaccine is the only one that's fully approved in the U.S., but the Moderna one is set for FDA review this week. And hopefully, if we see this similar data that’s coming out, will gain its approval as well.

So there's no direct head-to-head comparisons of each of the vaccines, but if there's similar vaccine efficacy of each compared with placebo, I think that patients should probably choose the one which is available for them the fastest, the one that they can receive the earliest.

Both vaccines from Pfizer and from Moderna have two doses. The booster shot (for Moderna’s vaccine) is four weeks after the first dose and Pfizer's is three weeks after the first dose.

It somewhat goes without saying that it’s crucial that all patients, whether they have cancer or not, really need to stay on that vaccination schedule?

Yes, I do think that booster is going to be necessary. And, you know, there could be a lag time of patients presenting with symptomatic COVID-19, and that's why we are seeing the early. But, certainly, that booster dose seems to be further protective, as evidenced by the patients who just have more symptomatic side effects from that second dose of the vaccine.

Was there anything else you wanted to mention about this topic?

These vaccines are intramuscular injections and likely will generate a type of antibody that's more systemic called IgG antibodies. So these antibodies are not the ones on the mucosal surface, which are more IgA antibodies. And so patients still could theoretically harbor the vaccine and pass it to others. And there are other patients who, as you mentioned, can't or won't receive the vaccine. And so that's why I think we should all still wear masks, avoid large gatherings and practice good hand hygiene until the time when we seem to have eliminated the COVID-19 threat.

We also don't know about long-term loss of immunity and when patients and people will need booster vaccinations. So there's many vaccines that adults receive booster vaccines for during their lifetimes, and potentially COVID-19 will be one of those. And I think that depends on long-term follow-up for these patients who have generously participated on the studies in terms of following their antibody titers, and when we think that these patients might lose their immunity.

So I think still a lot to learn as we follow these patients longer. But overall, with the approval of the vaccine, there is this glimmer of hope that sometime in the coming year, hopefully patients and people will all be protected through these vaccines. And hopefully we will all be safer and healthier.

This interview has been edited for clarity and conciseness

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