Vaccines are an important part of cancer care. Cancer itself, as well as treatments such as chemotherapy, immunotherapy, targeted therapy, radiation, stem cell transplant, CAR-T therapy, and some steroids or immune-suppressing medications, can weaken the immune system. This can make common infections more serious and harder to recover from.
Vaccines help lower the risk of certain infections and may reduce the chance of severe illness, hospitalization, and treatment delays. However, vaccine recommendations can vary depending on your age, type of cancer, treatment plan, blood counts, immune status, prior vaccines, and other medical conditions. Always discuss vaccines with your oncology team before receiving them, especially if you are currently receiving treatment or are about to start treatment.
General Principles
Timing matters
Whenever possible, recommended vaccines should be given before cancer treatment starts. This gives the immune system time to respond.
In general:
- Non-live vaccines are ideally given at least 2 weeks before starting chemotherapy or other strongly immune-suppressing treatment.
- Live-virus vaccines, when appropriate, should generally be given at least 4 weeks before starting immune-suppressing treatment.
- If treatment has already started, non-live vaccines can often still be given. The immune response may be weaker, but the vaccine may still provide meaningful protection.
- For patients who received anti-B-cell antibody therapy, such as rituximab, vaccination should be delayed for at least 6 months after the last dose, as patients generally do not mount an adequate response prior to B-cell recovery.
- Timing should be individualized based on treatment cycles, transplant status, and degree of immunosuppression.
Do not delay urgent cancer treatment just to complete vaccines unless your oncology team specifically recommends it.
Live vs. Non-Live Vaccines
Non-live vaccines
Most vaccines recommended for adults with cancer are non-live vaccines. These vaccines cannot cause the infection they are designed to prevent.
Examples include:
- Flu shot
- COVID-19 vaccine
- Pneumococcal vaccine
- Shingrix shingles vaccine
- RSV vaccine
- Hepatitis B vaccine
- Tdap/Td vaccine
Chemotherapy and other treatments may reduce how well the immune system responds to a vaccine. However, a lower response does not necessarily mean no protection. In many cases, some protection is better than none, especially for infections that can be severe in people with weakened immune systems.
Live vaccines
Live vaccines contain a weakened form of a virus. These vaccines are usually avoided during chemotherapy and other periods of significant immune suppression because the immune system may not be able to control even the weakened virus.
Examples of live vaccines include:
- MMR vaccine
- Varicella vaccine
- Nasal spray flu vaccine
- Live shingles vaccine, if used in countries where it is still available
Live vaccines should only be given if your oncology team confirms that it is safe for your specific situation.
Recommended Vaccines to Discuss With Your Oncology Team
Influenza vaccine: Yes
Adults with cancer should generally receive a flu vaccine every year.
The recommended vaccine is the flu shot, which is not a live vaccine. The nasal spray flu vaccine is a live attenuated vaccine and is not recommended for people who are immunocompromised.
Best timing:
- Ideally at least 2 weeks before starting chemotherapy or another immune-suppressing treatment.
- If that is not possible, it can often be given during treatment, preferably at a time when your oncology team expects your immune system to respond as well as possible.
Why it matters: Flu can be more severe in people with cancer and may lead to complications, hospitalization, or delays in cancer treatment.
COVID-19 vaccine: Yes
People with cancer should stay up to date with current COVID-19 vaccine recommendations. COVID-19 can be more severe in people with weakened immune systems, including many patients receiving cancer treatment.
COVID-19 vaccine recommendations change over time, so the number and timing of doses should be reviewed with your oncology team or primary care clinician.
Why it matters: Vaccination helps reduce the risk of severe COVID-19, hospitalization, and complications.
Pneumococcal vaccine: Yes
Pneumococcal vaccines help protect against infections caused by Streptococcus pneumoniae, including pneumonia, bloodstream infection, and meningitis. These infections can be more serious in people with cancer or weakened immune systems.
There are several pneumococcal vaccine options, and the best schedule depends on your age, immune status, and prior vaccine history. Common current options include PCV20 or PCV21 alone, or PCV15 followed by PPSV23 in selected cases.
Best timing:
- Ideally before starting chemotherapy or other immune-suppressing treatment.
- If you are already receiving treatment, your oncology team can help choose the best timing.
Why it matters: Pneumonia and invasive pneumococcal infections can be dangerous in immunocompromised patients.
Shingles vaccine: Yes, with Shingrix
Shingles is caused by reactivation of the varicella-zoster virus, the same virus that causes chickenpox. The risk of shingles can increase when the immune system is weakened.
The preferred shingles vaccine is Shingrix, also called recombinant zoster vaccine. It is not a live vaccine.
Shingrix is given as a 2-dose series. The doses are usually separated by 2 to 6 months. In some immunocompromised patients who need to complete the series sooner, the second dose may be given earlier, depending on clinician recommendation.
Important:
- Shingrix is not a live vaccine and is generally the preferred shingles vaccine for immunocompromised adults.
- Zostavax, the older live shingles vaccine, is no longer available in the United States. If a live shingles vaccine is available in another country, it should generally be avoided during chemotherapy or significant immune suppression.
Why it matters: Shingles can be painful and may cause long-term nerve pain, especially in people with weakened immune systems.
RSV vaccine: Yes, if eligible
RSV, or respiratory syncytial virus, can cause serious respiratory illness in older adults and people with weakened immune systems.
The RSV vaccines used for adults are not live vaccines. They cannot cause RSV infection.
Current recommendations generally include:
- All adults age 75 and older.
- Adults age 50 to 74 who are at increased risk for severe RSV illness, including many people with moderate or severe immune compromise.
- ASCO guidelines recommend that patients aged 60 years and older with cancer are eligible for RSV vaccination, noting it can be coadministered with other seasonal immunizations.
RSV vaccination is not currently an annual vaccine. Most eligible adults need only one dose, unless future recommendations change. RSV vaccine can be given to patients on chemotherapy.
Best timing: RSV vaccine can be given at any time of year, but late summer or early fall is often preferred before RSV season.
Why it matters: RSV can cause pneumonia, hospitalization, and severe respiratory complications in high-risk adults.
Hepatitis B vaccine: Yes, if not already immune
Hepatitis B vaccination is recommended for many adults, and it is especially important to review hepatitis B status before certain cancer treatments.
Your care team may order blood tests to check whether you:
- Are already immune from prior vaccination.
- Have had hepatitis B infection in the past.
- Have current hepatitis B infection.
The hepatitis B vaccine helps prevent new hepatitis B infection. It does not treat hepatitis B reactivation. If blood tests show current or prior hepatitis B infection, your oncology team may recommend monitoring or antiviral medication during cancer treatment.
Why it matters: Some cancer treatments can increase the risk of hepatitis B reactivation in patients who have current or prior infection.
What If I Already Started Cancer Treatment?
If you have already started chemotherapy or another cancer treatment, it may still be appropriate to receive non-live vaccines.
The vaccine response may be weaker during active treatment, but vaccination may still provide some protection. Your oncology team can help determine the best timing, such as between cycles or during a period when blood counts are expected to be more stable.
Do not receive live vaccines during chemotherapy or significant immune suppression unless your oncology team specifically says it is safe.
What About Family Members and Caregivers?
Vaccination is also important for people who live with or care for someone with cancer. When family members and caregivers are up to date on vaccines, they are less likely to bring infections into the home.
Caregivers should discuss their own vaccines with their healthcare provider, including flu, COVID-19, Tdap, and other age-appropriate vaccines.
Key Takeaways
- Vaccines are an important part of cancer care.
- Non-live vaccines are generally safe for people with cancer, although they may be less effective during active treatment.
- Live vaccines should usually be avoided during chemotherapy and significant immune suppression.
- When possible, vaccines should be given before treatment starts.
- If treatment has already started, it may still be worthwhile to receive recommended non-live vaccines.
- Always review your vaccine plan with your oncology team, because recommendations may differ depending on your cancer type, treatment, immune status, and prior vaccination history.
For Oncologists
ASCO guidelines recommend strongly that vaccination should ideally precede cancer treatment by 2-4 weeks, but emphasize that even if the ideal window cannot be met, non-live vaccine administration should still be strongly advised early in the treatment journey.
When the GI cancer patient is about to start chemotherapy in 2 weeks, a practical approach would be:
- Day 1, as soon as possible: Administer pneumococcal conjugate vaccine (PCV-20), Recombinant zoster vaccine (RZV, aka Shingrix) dose 1, Tdap if due, and influenza vaccine if in season. These can all be coadministered at the same visit at different injection sites.
- Same visit or within days: COVID-19 vaccine, current formulation. It can be coadministered with other vaccines.
- RSV vaccine: If the visit falls between August and October and the patient is considered at increased risk due to immunosuppression, this can also be coadministered.
- After chemotherapy starts: The second dose of RZV, 2-6 months after dose 1, and any remaining multi-dose series can be given during treatment, acknowledging potentially reduced immunogenicity.
