6% of cancer patients show little response to the COVID-19 vaccines after 4 weeks after second dose 

More than five percent of cancer patients exhibit no immune response to the two-shot COVID-19 vaccine, a new study suggests. 

Researchers found that 94 percent of patients developed antibodies after receiving the Pfizer-BioNTech or Moderna shots, but six percent did not – even four weeks after the second dose.

What’s more, participants who used a specific monoclonal antibody treatment within six months of vaccination did not develop antibodies.  

The findings build on past research that shows some cancer patients may still be vulnerable to coronavirus after vaccination.

Researchers say the lack of an immune response is troubling because it could mean some cancer patients who are already vulnerable to the virus may be left without means to protect themselves. 

A research team has found that 5% of cancer patients developed no antibody response to the COVID-19 vaccine even four weeks after receiving their second shot, leaving them vulnerable to the virus

The research team, from the Mays Cancer Center in San Antonio, Texas, and the University of Geneva in Switzerland, analyzed 131 active cancer patients that had received both shots of a two-dose mRNA vaccine.

Participants had a median age of 63 and 106 had a solid cancer rather than a hematological, or blood based, cancer. 

Findings, published in the journal Cancer Cell, showed that seven high risk patients has  no COVID-19 antibodies even three to four weeks after receiving their second dose.

This means that coronavirus vaccine may have no effect on the ability of cancer patients’ bodies to fight the virus. 

‘With other vaccines and infections, patients with cancer have been shown not to develop as robust an immune response as the general population,’ said Dr Ruben Mesa, senior co-author of the study and executive director of the Mays Cancer Center. 

‘It made sense, therefore, to hypothesize that certain high-risk groups of patients do not have antibody response to COVID-19 vaccine.’ 

Researchers also found a trend in types of treatment received.

They looked at patients who received Rituximab, a monoclonal antibody used to treat blood cancers and autoimmune diseases.

Those given the treatment did not develop an antibody response at all while those on chemotherapy developed a more muted response.

‘How that relates to protection against COVID-19, we don’t know yet,’ said corresponding author Dr Dimpy Shah of the Mays Cancer Centr. 

The team also found that those with blood-based cancers were less likely to develop an antibody response, and that the responses they developed were often weaker than others.

‘Patients with hematological malignancies, such as myeloma and Hodgkin lymphoma, were less likely to respond to vaccination than those with solid tumors,’ said Dr Pankil Shah, a co-lead author of the study.  

The results match those on an Israeli study from last month, which also found that people with blood based cancers were less likely to develop a strong antibody response to the COVID-19 vaccines. 

This study is unique, according to researchers, because it is the first to look at cancer patients after their body has had multiple weeks to develop antibodies.

Researchers still recommend that all cancer patients get vaccinated for COVID-19 no matter what, though they should still continue to take some precautions after vaccination. 

Cancer patients, and especially those with a blood based cancer, could be up to 70 percent more likely to die of coronavirus than the average person, making protection from the virus even more important.