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COVID-19 vaccination: Current recommendations for cancer patients in Singapore

As the national vaccination exercise vaccine is underway in Singapore, cancer patients here may have questions about the vaccine and whether they can take it. Dr Iain Tan Bee Huat, Senior Consultant in the Division of Medical Oncology, National Cancer Centre Singapore (NCCS) provides answers for patients and their caregivers.

1. I am a cancer patient, can I take the COVID-19 vaccine?

In Singapore, as of April 2021, patients with cancer who are not on treatment with chemotherapy, radiotherapy or immunotherapy can be vaccinated. The patient’s cancer treatment should have been completed three or more months before the vaccine is taken and there should be no plans for treatment in the next two months after the vaccine is taken.

Patients with a history of cancer, who are in remission, can be vaccinated. Patients on cancer hormonal therapy, can also be vaccinated.

If you’re in doubt about whether to take the vaccination, please check with your treating cancer specialist.

2. According to the criteria above, I’m not allowed to take the COVID-19 vaccine. Why is this?

The Expert Committee on COVID-19 Vaccination appointed by the Singapore Ministry of Health (MOH) has made recommendations for which groups of patients can take the COVID-19 vaccines and which groups should wait for further information. NCCS is engaged and working with the Expert Committee on these recommendations.

The COVID-19 vaccine trials were performed in the general population and generally did not include patients undergoing chemotherapy, immunotherapy or radiation therapy.

Chemotherapy can affect the immune system. There is concern that patients on chemotherapy may not be able to mount an effective immune response against COVID-19 and thus, the level of protection against the virus could be less effective. With immunotherapy, there is concern that the vaccination may increase the risk of immune-related side effects of immunotherapy.

Due to the small number of cancer patients included so far in COVID-19 vaccination clinical trials, it is difficult to completely determine the effectiveness and safety of COVID-19 vaccines for cancer patients. The Expert Committee has therefore recommended that cancer patients on treatment are not currently eligible for vaccination.

NCCS, administering hospitals and MOH are constantly reviewing international medical literature on emerging data on the immunogenicity (effectiveness) and safety of the COVID-19 vaccines. As safety and effectiveness data emerges, the recommendations for vaccination will be adjusted.

For patients with a defined duration or course of treatment, we ask them to complete their treatment first, wait three months after completion and then consider registration for vaccination.

For patients receiving ongoing treatment, we ask that patients wait for more information and recommendations from MOH regarding COVID-19 vaccination.

3. According to the criteria above, I’m allowed to take the vaccine, how do I register?

If you are an NCCS patient, you have two options to get the COVID-19 vaccination.

a)       Register for vaccination as part of the national COVID-19 vaccination programme. COVID-19 vaccination began on 22 February 2021 and is being done in phases according to age groups, starting with seniors above 70. You can expect to receive a letter of notification from the Ministry of Health. In that letter you will be directed to register for vaccination at

b)      Seek your doctor’s advice at your next outpatient consultation at NCCS and register for vaccination at the Singapore General Hospital Vaccination Clinic at Bowyer, if you are eligible and have no medical contraindications.

For more information on COVID-19 vaccination for NCCS patients, please click here.

4. How do I protect myself against COVID-19, if I cannot be vaccinated at this time?

COVID-19 vaccination is a part of a broader set of measures to protect the public health of Singaporeans. Like the general public, cancer patients who are not recommended to take the vaccine presently are advised to continue practicing recommended safety and social distancing measures (outlined under COVID-19 Phase 3 measures) to reduce the risk of disease transmission. We note that with effective measures, there remains zero to low community cases, presently. Continued vigilance by everyone will help all of us protect one another. In addition, family members in the same household of unvaccinated cancer patients are encouraged to participate in the national vaccination exercise.

Should women delay mammograms if taking the COVID-19 vaccination?

By: Dr Jill Wong Su Lin, Senior Consultant, Division of Oncologic Imaging, NCCS

Concerns that one of the possible side-effects of the COVID-19 vaccine are enlarged lymph nodes, have caused women to ask if they should go for their regularly scheduled mammogram screening. If you have an upcoming mammogram screening, here is what you should take note of:

  • Based on data from the United States, women should wait four to six weeks after their second COVID-19 vaccination before having their screening mammogram. This is to prevent any possible concern that could result from swollen lymph nodes that are a possible side effect of COVID-19 vaccination.
  • If you have significant symptoms such as a lump or nipple discharge, consult a breast surgeon early and do not wait four to six weeks after COVID-19 vaccination to get checked.
  • If you have enlarged lymph nodes that appear on the mammography scan, radiologists will evaluate the breast for cancer and for other possible non-malignant causes such as any recent infection, skin problems, joint problems and inflammation in the arm or recent COVID-19 vaccination, which could cause lymph node enlargement.

At the time of publication, we have not encountered many women of screening age (40 to 70 years) who have requested deferment of their mammograms due to COVID-19 vaccination. We will continue to monitor the situation and update recommendations.