Cancer patients may not be as protected by the first dose of the Pfizer vaccine
Thursday 11 March 2021
A small-scale research study is reporting that cancer patients may be less protected against Covid-19 than other people after one dose of the Pfizer vaccine.
The study by researchers from King's College London and the Francis Crick Institute recruited 205 people, included 151 with solid cancers, such as lung, breast and bowel, and those with blood cancers. Volunteers were tested volunteers for antibodies and T-cells in their blood, which signals that the immune system can protect against illness from the virus in the future.
Three weeks after one dose, an antibody response was found in:
- 39% of people with solid cancers
- 13% of people with blood cancer
- 97% of people with no cancer
Following a second dose three weeks after the first, which some cancer patients received, there was a sharp rise in their antibody response against the coronavirus, to 95%.
But among those who had to wait longer for their second dose, there was no real improvement in protection. Five weeks after the first dose, an antibody response was detected in:
- 43% of people with solid cancers
- 8% of people with blood cancer
- 100% of people with no cancer
In trials of the Pfizer vaccine, two doses were given three weeks apart and although a longer gap between doses works for healthy individuals, the researchers say cancer patients do not respond in the same way.
Dr Lisa Wilde, Director of Research and External Affairs at Bowel Cancer UK, says: "We're pleased to see research looking at how effective coronavirus vaccines are for bowel cancer patients, however, we need to remember that this current study is very small scale, only focused on one of the licensed vaccines available in the UK, and is yet to be reviewed by other scientists.
"What we need now is larger scale research on the vaccines effectiveness in cancer patients, alongside guidance from the Joint Committee on Vaccination and Immunisation (JCVI) on the most appropriate timings of a first and second dose. We'll be raising this issue, along with other cancer charities, directly with the vaccine minister.
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