COVID-19 Vaccines and Cancer


COVID-19 Vaccines

Both the Pfizer-BioNTech COVID‐19 and Moderna vaccine received an emergency use authorization (EUA) from the United States Food and Drug Administration (FDA) for use for active immunization to prevent COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in individuals 16 years of age and older Johnson & Johnson intends to file for Emergency Use Authorization shortly and expects to have the vaccine available to ship immediately in February if authorized.

Vaccination is currently prioritized for essential workers, people over age 65 and individuals with underlying health conditions that increase the risk for severe COVID-19. These health conditions include cancer, obesity, heart disease, lung disease but not immunocompromised individuals.

How Do the Vaccines Work?

A vaccine is designed to trigger a controlled immune system response that trains the body to fight a foreign invader (virus, bacteria) if the body encounters the invader again in the future. The coronavirus is studded with spike proteins that protrude and allow the virus to enter your cells where they start replicating. Spike proteins are recognized as “foreign” and serve as a target for the immune system.

The two vaccines are the first of a new type of vaccine based on messenger RNA (mRNA). Instead of injecting a weakened or killed virus into the body, mRNA vaccines teach cells how to make a protein—or even just a piece of a protein—that triggers an immune response.

How is the vaccine given?

The vaccine is injected into the muscle of your upper arm. The vaccine is given in 2 doses at 21 days interval and we expect patients receiving the vaccine to be immune 2-3 weeks after their second dose of vaccine.

How effective are the mRNA vaccines?

Both vaccines appear highly effective resulting in a measurable immune response in over 94% of vaccinated individuals by seven days after getting the second dose. Because it takes your body about two weeks to make enough antibodies to mount a response to the virus an immune response is evident as early as 14 days after the first dose, but the effectiveness was only about 50%. (1,2,3) According to Moderna the vaccine may be effective up to one year.

Johnson & Johnson COVID Vaccine

The Johnson & Johnson vaccine candidate unlike Pfizer and Moderna, uses a human adenovirus that has been modified to no longer replicated in humans and cannot cause disease. The vaccine is reported to be 66% effective in preventing moderate to severe COVID-19 at 28 days post-vaccination. The vaccine is reported to be 85% effective in preventing severe/critical COVID-19. Moreover, the vaccine demonstrated complete protection against COVID-19 related hospitalization and death at 28 days post vaccination. Onset of protection was observed as early as day 14 and there were no reported COVID-19-related deaths in vaccinated individuals. The Company intends to file for Emergency Use Authorization and expects to have the vaccine available to ship immediately if authorized.(9,10)

COVID Vaccination and Cancer – Answers to Frequently Asked Questions

Are doctors recommending vaccination to all cancer patients?

Having cancer regardless of treatment status is a risk factor for worse outcome from infections including influenza and COVID-19. The short answer is yes once COVID-19 vaccines become more widely available. In terms of prioritization, and according to CDC guidelines, cancer patients will be part of the phase II wave of vaccination which will occur sometime in February. The vaccine is given in 2 doses at 21 days interval and we expect patients receiving the vaccine to be immune 2-3 weeks after their second dose of vaccine.

For newly diagnosed cancer patients - will the goal be to vaccinate before treatment?

Ideally, it is best to vaccinate before treatment as the immune response to the vaccine may be impaired in patients receiving chemotherapy. The vaccine is optimally administered at least two weeks before chemotherapy starts.

If on chemotherapy or immunotherapy will treatment be changed in anyway in order to vaccinate?

Other than timing, there should be no major changes to your plan of treatment relative to vaccine administration. It is important to note that other measures taken by your treating physician about the safety of administering the vaccine such as blood counts, concern regarding allergic reactions and others should be taken in consideration to decide on timing and appropriateness of vaccination.

How soon can vaccination occur after completion of chemotherapy or immunotherapy?

There have been conflicting results regarding the immunogenicity of immunization on the first day of the chemotherapy cycle, with one study showing poor immune protection but another study showing good protection from the flu vaccine. Since there is not enough data for the COVID vaccine, we assume similarities and recommend vaccination at the one-week mark from the start of the chemotherapy cycle.

Regarding immunotherapy, studies are relatively conflicting, but a recent study suggests that the flu vaccine does not worsen the toxicities of this type of therapy. Since COVID-19 infection can be very severe and potentially lethal for patients undergoing chemotherapy or immunotherapy, we will be recommending vaccination for all patients with cancer as we continue to study this question further.

What SARS-CoV-2 vaccines are approved for use in immunocompromised patients?

No current clinical trials of a COVID-19 vaccine have enrolled immunocompromised patients. Thus, the effectiveness and safety of a SARS-CoV-2 vaccine has not been established in the different immunocompromised patient populations.

Why might some cancer patients not respond to vaccines?

In order for the vaccine to generate protective immunity functional host immunity is required. The host must be able to correctly present the antigen to the immune system so B and T cell activation can occur, and plasma B cell antibody generated. People lacking functional adaptive immune cells may be unable to generate a fully protective immune response to a SARS-CoV-2 vaccine.

According to the American Society of Hematology the following immunocompromised patients could have attenuated or absent response to a SARS-CoV-2 vaccine. (4)

  • Immunodeficiencies involving adaptive immunity
  • Splenectomy or functional asplenia (sickle cell disease)
  • B cell directed therapies against CD20 or CD22, bispecific agents like blinatumomab, CD19 or CD22-directed CAR-T cell therapies and BTK inhibitors)
  • T cell directed therapies (antithymocyte globulin, alemtuzumab)
  • Many chemotherapy regimens
  • High-dose corticosteroids
  • Stem Cell Transplant patients - especially within the first 3-6 months after autologous and often longer after allogeneic.
  • Graft-vs.-host disease (GVHD)
  • Low white blood cell counts. (neutropenia ANC<500/μL, lymphopenia ALC<200/μL)

What is known about the safety and efficacy of protein-based or killed (inactivated virus) vaccines in immunocompromised patients?

Long-term side effects have not been defined for SARS-CoV-2 vaccines and will be available once phase 3 trials have followed longer. A national monitoring system exists for reporting vaccine-related adverse events.

Are there and theoretical concerns with RNA vaccines in immunocompromised patients?

Theoretical concerns for their use include a hyper-inflammatory response, which was described in some animal models. (5) This effect has not been demonstrated in humans. Another concern is the development of autoimmune syndromes related to the increased type I interferon response elicited by an mRNA/DNA vaccine. (6)

Given patients with chronic lymphocytic leukemia, lymphoma or myelodysplasia and patients after allogeneic hematopoietic cell transplantation may be prone to other immune-mediated complications, there is some concern that generating anti-SARS-CoV-2 antibodies in these patients could lead to immune enhancement and a systemic inflammatory response akin to what is seen with multisystem inflammatory syndrome in children (MIS-C).

If immunocompromised patients were not included in the vaccine trials and are less likely to respond to a SARS-CoV-2 vaccine, should they still receive it?

Most experts recommend vaccination as long as the vaccine is safe for use, even if the expected protection rate is lower than the general population because the risks of getting COVID-19 infection in patients with cancer is significant.

The risks and benefits for immunocompromised patients receiving a SARS-CoV-2 vaccine should be weighed on a case-by-case basis, with consideration of the incidence of infection in the community. This will depend on the approved vaccine formulation available, level of immunosuppression the patient has received, and the underlying reason for immunosuppressive therapy (e.g., cancer treatment, transplantation).

When should patients on immunosuppressive therapy by vaccinated?

Vaccination is recommended at least 2-4 weeks prior to the planned immunosuppressive therapy, transplant or splenectomy. If the patient is receiving or has received immunosuppressive therapy, consider vaccination 6 months after the patient has been taken off therapy to increase the likelihood of developing immunity. After hematopoietic cell transplantation vaccines are generally started after 3-6 months.

What Don't we know about the Vaccines?

  • Does vaccination protect against asymptomatic cases of COVID-19?
  • Does vaccination prevent transmission of COVID-19?
  • How long does protection last?

Until this data is available, it’s important to remember that getting vaccinated is not a passport to a pre-COVID life. People who are vaccinated still need to wear face masks and practice social distancing.

Who should not get vaccinated?

The fact sheet says that you should not get the Pfizer-BioNTech COVID-19 vaccine if you:

  • had a severe allergic reaction after a previous dose of this vaccine
  • had a severe allergic reaction to any ingredient of this vaccine

What if I have a history of allergies?

The American College of Allergy, Asthma, and Immunology released a statement offering guidance to patients with allergies. (7)

  • Allergic reactions to vaccines, in general, are rare with the incidence of anaphylaxis estimated at 1.31 in 1 million doses given.
  • Individuals with common allergies to medications, foods, inhalants, insects, and latex are no more likely than the general public to have an allergic reaction to the Pfizer-BioNTech COVID-19 vaccine. Those patients should be informed of the benefits of the vaccine versus its risks.
  • The Pfizer-BioNTech COVID-19 vaccine should be administered in a health care setting where anaphylaxis can be treated. All individuals must be observed for at least 20-30 minutes after injection to monitor for any adverse reaction. All anaphylactic reactions should be managed immediately, with epinephrine as the first line treatment.
  • The Pfizer-BioNTech COVID-19 vaccine should not be administered to individuals with a known history of a severe allergic reaction to polyethylene glycol as it is a component of this vaccine that is known to cause anaphylaxis.
  • Data related to risk in individuals with a history of allergic reactions to previous vaccinations and/or mast cell activation syndrome/idiopathic anaphylaxis is very limited and evolving. A decision to receive the Pfizer-BioNTech COVID-19 vaccine should be undertaken by you with your physician or other provider administering the vaccine using their professional judgment balancing the benefits and risks associated with taking the vaccine.

What are the vaccine’s side effects?

The most common side effects reported in the clinical trials were pain at the injection site, fatigue, and fever. Serious side effects were rare and other reported side effects of the vaccines include:

  • Injection site pain
  • Tiredness
  • Headache
  • Muscle pain
  • Chills
  • Joint pain
  • Fever
  • Injection site swelling
  • Injection site redness
  • Nausea
  • Feeling unwell
  • Swollen lymph nodes (lymphadenopathy)

Are the Pfizer and Moderna COVID-19 vaccines considered “live”?

No, the vaccines are not live vaccines.

My friend says that the pfizer mrna vaccine may cause covid19 illness in some people, is it true?


Until the safety of the vaccine is proven with more studies, the only proper recommendation about the use of the COVID vaccine should be for a measured approach while carefully considering each patient’s risk factors for serious complications from the infection. This is a personalized decision between the patient and their providers. Most oncologists will recommend the COVID-19 vaccine to all their patients regardless of their treatment status taking into account all of the points above.

Recommendations may change, based on the results of the approved vaccine trials.

The "Ask The Experts" About COVID-19 and Cancer Series


  1. Pfizer COVID-19 Vaccine EUA Letter of Authorization reissued 12-23-20
  2. Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine
  3. Voysey M, et al. Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. The Lancet. December 8, 2020. [doi](
  4. ASH-ASTCT COVID-19 and Vaccines: Frequently Asked Questions
  5. Bos R, Rutten L, van der Lubbe JEM, et al. Ad26 vector-based COVID-19 vaccine encoding a prefusion-stabilized SARS-CoV-2 Spike immunogen induces potent humoral and cellular immune responses. NPJ Vaccines 2020;5:91.
  6. Pardi N, Hogan MJ, Porter FW, Weissman D. mRNA vaccines - a new era in vaccinology. Nat Rev Drug Discov 2018;17:261-79.
  7. Reynolds E, et al. Allergy warning for Pfizer/BioNTech vaccine after UK health workers with allergy history suffer reaction. CNN. December 10, 2020.
  8. Johnson & Johnson announces single-shot Janssen COVID-19 vaccine candidate met primary endpoints in interim analysis of its phase 3 ENSEMBLE trial. [press release]. New Brunswick, NJ: Johnson & Johnson; January 29, 2021.
  9. Janssen investigational COVID-19 vaccine: interim analysis of phase 3 clinical data released. [press release]. Bethesda, MD: National Institutes of Health; January 29, 2021.
Comments (9)
No. 1-4

Hi, 1) what is your root info source on the section on timing of vaccine administration (ideally 2 weeks before chemo)? Would like to read more closely.
2) where would you put radiation therapy and targeted immunotherapy Herceptin patients in terms of the concerns your raise about administering to patients currently on chemo? (Again, timing and also fear of lack of efficacy?)


Would there be any particular timing for a vaccination for a patient with marginal cell leukemia, first Rituximab treatment March 2020, being followed by maintenance every 6 months (Ocotober 2020, May 2021 etc for 2 years) Pretty sure only mRNA is available.



Its hard to know for sure given the vaccines were not evaluated in lymphoma patients. The oxford vaccine appears to be less effective than the mRNA but is more of a known quantity and being a year out from treatment you should be capable of mounting an immune response. The risk of taking the vaccine is very low and the potential benefit is real.

Jasojit Mookerjea
Jasojit Mookerjea

We are in India where there is no mRNA vaccine as yet. The available vaccine is the Oxford University-Astra Zeneca vaccine Chadox. How effective is this vaccine likely to be for a 64 year old Non Hodgkin Lymphoma (Follicular) patient currently in remission ( last chemotherapy- R-CHOP in Aug 2019 and last Rituximab maintenance dose in Feb 2020) ?

Treatment & Care