COVID Vaccines Are Far Less Effective in Most Cancer Patients, Ineffective in Some, According to New Research

Research supports a need for booster shots in cancer patients.

Published Aug 11, 2021

Chris Spargo

COVID vaccines are far less effective in cancer patients receiving chemotherapy, immunotherapy, biological therapy, or any combination of the three; and ineffective in many who have been diagnosed with cancer of the blood.

A pair of studies published in The Journal of the American Medical Association show that cancer patients have fewer antibodies than individuals who are not immunosuppressed when they first receive the vaccine, and after their second dose.

These studies both lend further credence to the belief that a third vaccine shot would benefit cancer patients, but stop short of advocating for a booster.

The first of these studies examined the antibody levels in patients with solid tumors on active anticancer treatment versus healthy controls in the weeks after receiving the second dose of the Pfizer vaccine.

There was some good news for cancer patients, with 90% of the participants registering as seropositive – meaning a blood test showed evidence of COVID antibodies – 5.5 weeks after the second dose and 87% four months after that final vaccination.

By comparison, all 66 controls were seropositive for COVID antibodies both 5.5 weeks and four months after they received the second dose of the vaccine.

The big difference was in the level of antibodies present in cancer patients versus the healthy controls.

Related: Cancer Patients Face ‘Life or Death’ Decisions As Hospitals Overrun with COVID Postpone Critical Surgeries and Treatments

Cancer patients had about a quarter of the antibodies that healthy individuals did after 5.5 weeks and then a little less than a third after four months.

Cancer patients had lost 78% of their antibodies after four months while the healthy control lost 82% between the two tests.

The second study focused on 160 patients with hematologic (blood) cancers and found that only 39% of participants tested positive for COVID antibodies after receiving the vaccination.

There were 82 individuals receiving treatment, 63 in remission, and 15 who were not seeking treatment at the time time of the study.

Of that group, there was no seroconversion in 60 (73%) of the individuals receiving treatment, 30 (47%) in remission and 5 (33%) not seeking treatment.

The study notes: “[O]ur findings raise a concern that patients with hematologic cancers, particularly those receiving B-cell–depleting immunotherapy, may not gain adequate protection from vaccination, and as observed in our cohort, may still develop a potentially fatal infection.”

It goes on to say that “these patients may benefit from ongoing protective measures, including masks, social distancing, and screening” and that “consideration should be made to prioritizing vaccination for family members and caregivers to protect the patients themselves.”

Related: COVID Patients Suffering Greater Mental, Physical Declines Than Some Cancer Patients At Rehab Facilities, According to New Research; How To Stay Safe Amid Uncertainty

How Cancer Patients Can Stay Protected From Dangerous Variants of COVID-19

Multiple oncologists tell SurvivorNet that wearing a mask is still the best way for cancer patients to avoid contracting or spreading the virus as the dangerous Delta variant surges across the country.

At the same time, a game-changing COVID-19 booster may soon be available for cancer patients who are looking to develop or maintain antibodies against the virus.

SurvivorNet recently spoke with multiple oncologists who were strongly in favor of these booster shots, which Moderna plans to roll out in November and Pfizer is trying to offer in August.

Dr. Paul G. Richardson, clinical program leader and director of clinical research at the Jerome Lipper Multiple Myeloma Center at Dana-Farber Cancer Institute, noted, however, that getting vaccinated is just one of many steps cancer patients should be taking at this time.

“The key is the success of vaccinations, but other strategies in my [multiple myeloma] patients focus on continued precautions, and attention to therapeutics – not least as the variants are such a concern,” explained Dr. Richardson.

“We are moving from pandemia to endemia and as such long-term adjustments and continued caution are inevitable in terms of treatments for underlying and supportive care. Fortunately, however, we are moving towards a more manageable paradigm of therapy/care, although the danger of SARS CoV2 remains clear and present.”

5 COVID-19 Vaccine Questions Answered by Expert Physician

Individuals with cancers of the blood, those who are undergoing chemotherapy, or patients who recently had any sort of stem cell transplant are the most vulnerable due to the increased risk that their bodies may not produce any antibodies against COVID-19 even after receiving two doses of the vaccination.

That is why masks are so important for individuals with cancer.

“The problem with a lot of the variants, especially the Delta variant and others, is that if you have a low immune response or low antibody titer, which many of these (cancer) patients would have, it may not be protective against getting an infection,” explained Dr. John N. Greene, chief of infectious diseases at the Moffitt Cancer Center.

“So for these immunosuppressed cancer patients, there is no guarantee that their vaccine is effective because [antibody testing] is not recommended outside of a research setting to actually measure their immune response or their antibody levels. And therefore, since it remains a mystery, they should continue to wear a mask and not go into large crowds where people could infect them and others visiting them.”

He continued: “I think that’s pretty sound logic because these immunosuppressed patients and people are at higher risk of serious illness if they were to catch COVID-19.”

Dr. Amrita Krishnan, director of the Judy and Bernard Briskin Center for Multiple Myeloma Research at City of Hope, told SurvivorNet that she continues to urge her patients – many of whom are at a high risk of not producing antibodies – to wear a mask and social distance.

Dr. Jana Dickter, also from City of Hope, said that it is not just those with cancer who need to be careful.

“I would also suggest that patients advocate for themselves by having close relatives, family members, and household contacts get vaccinated,” Dr. Dickter told Survivor Net.

There may also be a third option in the near future, and a special vaccine is currently in development.

The National Cancer Institute is sponsoring a trial for a vaccine that is specifically designed to protect individuals with cancer from contracting COVID-19. That trial is still in the recruiting stages.

COVID-19 Has Changed Surgery and Hospital Protocols for Cancer Patients

Learn more about SurvivorNet's rigorous medical review process.


Chris Spargo is a senior reporter at SurvivorNet. Read More