COVID-19 vaccines ARE effective in cancer patients: Study finds 94% of patients developed antibodies

Cancer patients do develop COVID-19 antibodies after being fully vaccinated, a new study suggests.

Researchers from Montefiore Health System and Albert Einstein College of Medicine in the Bronx, New York found that 94 percent of patients with tumors developed antibodies after being vaccinated.

Even patients receiving stem cell transplants and other treatments that suppress the immune system had antibody positivity rates over 70 percent.

This finding is great news for many patients and their physicians who worried that the vaccines would not be effective for cancer patients. 

The teams says the findings provide evidence for why patients should definitely get vaccinated against coronavirus if a shot is available to them.

Out of 200 patients in a Bronx, New York study, 94% developed COVID antibodies after being vaccinated. Pictured: Acancer patient receives her vaccine while others talk and laugh in an oncology unit at James Graham Brown Cancer Center in Louisville, Kentucky, April 2021

Cancer patients taking stem cell treatments and other therapies had lower antibody responses, but still saw definite immune system buildup after being vaccinated

Cancer patients taking stem cell treatments and other therapies had lower antibody responses, but still saw definite immune system buildup after being vaccinated

Cancer patients are among those most vulnerable to severe COVID-19.

Many of the treatments used to treat different forms of cancer can cause the immune system to lose its ability to fight off disease.

Elderly cancer patients and those who also suffer from other conditions – like lung disease or diabetes – are especially vulnerable because they have weak immune systems, or are immunocompromised.

In one May 2021 study, researchers estimated that about 90,000 American adults under age 65 are immunocompromised. – representing about three percent of the population.

Due to their weaker immune systems, many medical experts have worried that vaccines would not be effective for cancer patients.

So far, studies in this area have been limited because COVID-19 vaccine trials excluded patients with cancer diagnoses. 

Patients have not been able to get clear information on whether they should get vaccinated – or how the vaccines may impact their cancer treatment. 

The new study, published in the journal Cell, included 200 patients from the Bronx, New York, who got tested for COVID antibodies after they were fully vaccinated. 

The majority had an active cancer diagnosis, and 56 percent were on active chemotherapy, including 19 percent who had received chemotherapy within 48 hours of at least one vaccine dose.

All common cancer types were represented in the study.

Cancer patients built up immune responses to the coronavirus after being vaccinated

Cancer patients built up immune responses to the coronavirus after being vaccinated

Out of those 200 patients, a whopping 94 percent tested positive for COVID-19 antibodies after vaccination – meaning they had successfully built up an immune response to the coronavirus.

Most of the patients had received the Pfizer and Moderna vaccines, while a few received the Johnson & Johnson vaccine. Those who had Pfizer and Moderna shots were slightly more likely to test positive for antibodies.

The researchers also found that antibody levels were higher when patients were tested with more time after their final vaccine dose – reflecting how antibody levels build up over time.

Patients had common mild side effects, such as sore arms and muscle aches.

‘The side effects from vaccination seen in these populations were not substantially worse than in other groups,’ said Dr Balazs Halmos, director of the Multidisciplinary Thoracic Oncology Program at Montefiore and a senior author on the study, in a statement. 

‘Not a single patient had to go to the emergency room or be admitted to the hospital because of side effects from the vaccines.’

Some of the cancer patients did have slightly lower antibody positivity rates such as those with blood cancers had a positivity rate of 85 percent, compared to 98 percent positivity for patients with solid tumors.

Patients receiving specific therapies that kill B cells and those who recently had bone marrow or stem cell transplants were also less likely to test positive for COVID antibodies. 

Still, these patients had positivity rates over 70 percent – higher than the researchers had expected.

The researchers also noted that there was no significant difference in vaccine effectiveness for patients of different racial/ethnic groups.



This study has been the largest so far looking at vaccine effectiveness in cancer patients – previous studies have examined smaller numbers of patients.

The findings suggest that cancer patients can – and should – get vaccinated without worrying about side effects, and they may be confident that their immune systems will respond to the shots.

‘We really need efforts to protect these vulnerable patients from infection,’ said Dr Amit Verma, director of the Division of Hemato-Oncology at Montefiore and another coauthor on the study. 

‘This study should help people feel reassured that these vaccines work very well, even in those receiving chemotherapy or immunotherapy.’

More research is needed to confirm this study’s findings and to examine the potential use of higher vaccine doses or booster shots for cancer patients.

Still, the study’s message is clear: ‘It’s important to stress how well these patient populations did with the vaccines,’ Verma said.