A second dose of the vaccine in three weeks, however, increased its protection significantly, with the researchers calling for previous increases in this group in the United Kingdom. The UK’s vaccination strategy currently involves a 12-week interval between doses of coronavirus vaccines; Pfizer recommends 21 days between doses.
The study looked at the impact of the Pfizer-BioNTech vaccine on 205 participants – 54 healthy volunteers and 151 elderly patients with solid cancers, such as breast or prostate cancer, and hematological (blood) cancers, such as leukemia. The prepress study has not yet been peer-reviewed or published.
The researchers looked at the levels of antibodies and T cells in the blood to identify the level of immune response generated against the coronavirus.
Three weeks after a dose of the vaccine, an antibody response was found in 39% of patients with solid cancer and only 13% of people with blood cancer. The response in healthy volunteers was 97%.
In solid cancer patients who received a second dose three weeks after the first, the antibody response skyrocketed to 95% in two weeks after booster. Sufficient booster vaccines were not administered to patients with blood cancer to determine the response in that group.
Further evidence of the need for a booster was shown by the fact that antibody levels only increased to 43% in people with solid cancers and 8% in those with blood cancer five weeks after the first dose. It was 100% in healthy volunteers.
“Our data provide the first real evidence of immunological efficacy after a dose of the Pfizer vaccine in populations of immunocompromised patients. We show that after the first dose, most patients with solid and hematological cancer remained immunologically unprotected until at least five weeks after the injection. primary, but this low dose effectiveness can be redeemed with an early boost on the 21st, “said Dr. Sheeba Irshad, a senior clinical professor at the School of Cancer and Pharmaceutical Sciences who led the research.
“Based on our findings, we would recommend an urgent review of the vaccine strategy for clinically extremely vulnerable groups. Until then, it is important that cancer patients continue to observe all public health measures in place, such as social detachment and protection, while attending hospitals, even after vaccination, “added Irshad in a statement.
Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, stressed that certain limitations must be taken into account.
“The change in UK policy on postponing a second dose of the vaccine has allowed the authors to make some comparisons between those who received a second dose in 21 days and those who did not. They have not yet provided data on those who received a second dose. dose after a 12 week delay, “he said in a statement to the UK’s Science Media Center.
“However, these results suggest that vaccines may not protect cancer patients as well as those without cancer,” he added.
“All of these findings are consistent with our understanding of the function of the immune system in cancer patients,” said Shoba Amarnath, a researcher at Newcastle University Center for Cancer. “We know that the immune system within cancer patients is compromised compared to healthy controls. Therefore, a second vaccine booster prepares the deregulated immune system to function as efficiently as healthy controls.
“The study data supports the notion that, in patients with solid cancer, a considerable delay in the second dose will extend the period when cancer patients are at risk of SARS-CoV-2 infection.”