Throughout the pandemic, evidence has been growing that for most people with cancer, Covid-19 vaccines are effective. But people with blood cancers are often treated with aggressive therapies which can impact their immune systems and therefore reduce their ability to respond to Covid-19 vaccines and gain their protective effect.
This, combined with the fact that people with blood cancer typically have more severe Covid-19 outcomes means the pandemic has been a particularly challenging time for many people with blood cancer and their families. But there is some reassuring news in the form of a new study led by researchers in Germany.
The work was published last week in the journal Nature Cancer and involved 60 patients with two types of blood cancer; multiple myeloma and B-cell lymphoma. The study followed the patients over time and looked in detail at their immune responses after three Covid-19 vaccines.
Most research studies assessing immunity to Covid-19 after vaccination only look at antibody titers, that is the amount of antibodies in the bloodstream directed to the SARS-CoV2 Spike protein. This is partly because it is the easiest and cheapest way to assess immunity, but the immune system consists of many interconnecting parts and antibodies do not tell the whole story.
Previous research has shown that people with blood cancers on certain therapies have a low antibody response to Covid-19 vaccines. Patients receiving therapies which target cells called B-cells, which produce antibodies, were previously thought to gain minimal benefit from vaccination because they were found to have low or undetectable antibody levels after vaccination.
But more recent work has suggested that even in patients which produce an undetectable, or low quantity of protective antibodies after vaccination, another type of immune cell; a T cell is activated and can provide protection.
“Our results show that almost all study participants had a strong T cell response to Covid-19 vaccination,” explains Dr. Andrea Keppler-Hafkemeyer, lead author of the work from the Medical Center-University of Freiburg.
Similar to previous studies, patients with blood cancer in the study had significantly lower antibody concentrations against the Covid-19 Spike protein in their blood than healthy subjects who were used as a comparison. But what was more surprising was that even with much lower antibody levels on average, the quality of the antibodies they did produce was actually higher than for healthy controls. The researchers showed that these antibodies were able to neutralize several different SARS-CoV2 virus variants, including the Omicron BA.1 strain.
“Covid-19 vaccination can generate very broad antiviral immunity – including highly potent neutralizing antibodies – in patients with various types of blood cancer,” said Professor Oliver T. Keppler, the senior author of the study from the German Center of Infection Research at Ludwig-Maximilians University in Munich.
Throughout the follow-up period of the study, some of the patients did get sick with Covid-19, but for most of the participants, infection was mild or moderate, even if they hadn’t formed any detectable protective antibodies after vaccination.
The new work gives further reassurance to patients with blood cancer that in most cases, they should gain some benefit from Covid-19 vaccination, even if they have undetectable or low antibodies.
“Multiple vaccine doses can be recommended for patients with B-cell lymphoma or multiple myeloma without interrupting therapy,” said Professor Keppler.