Cancer patients with solid tumours who did not respond to their first two doses of the Covid vaccine have shown a detectable antibody response after a third booster dose, according to a new study.

The CAPTURE study, published in Cancer Cell, showed that for patients with solid tumours and hematologic malignancies, a third dose of the Covid vaccine can help to protect against the initial virus and Beta and Delta variants.

Not all patients appeared to benefit from booster dose

The findings show that people with blood cancer who had a response after two doses also had a better response against all variants after their third dose.

However, not all patients benefitted. Around half of people with blood cancer who did not have a detectable response against the Delta variant after two doses, still had no detectable response after three doses.

This supports findings from the previous CAPTURE study which found that people with blood cancer showed a poorer immune response to the first two doses of a Covid vaccine compared to people with solid tumours.

Cancer Research UK say more research will need to be done to confirm the findings

The study also looked at the T cell response (a type of white blood cell) in a subset of patients and found that this was boosted after a third dose in both people with solid tumours and blood cancers, potentially offering additional protection.

Cancer Research UK warn that as the study only included a relatively small number of participants, more research is needed to understand how effective the Covid vaccines are for people with cancer.

Until then, they recommend that anyone undergoing cancer treatment “to follow the recommendations of their doctors and specialists”, and they encourage “all who have been offered the vaccine to take it.”

Pre-print study shows booster could also help to protect against Omicron

Another study has shown that a third dose of any mRNA vaccine could provide cancer patients with strong protection from the latest variant of concern, Omicron.

A booster dose was shown to produce higher neutralizing antibody (nAb) levels as well as greater breadth of neutralization, according to the pre-print paper published in medRxiv.

The results showed that after two doses of an mRNA vaccine, the neutralization titer against the Delta variant reduced by 4-fold, while against Omicron it was reduced 21-fold, compared to D614G mutation.

The study’s authors conclude: “Our results demonstrate that patients with cancer who received booster dose of mRNA vaccine displayed a significantly greater neutralising capacity against the Omicron variant in comparison to those recipients of two-doses of mRNA vaccine.”