A second dose of vaccine at three weeks, however, significantly increased their protection, with researchers calling for earlier boosts in this group in the UK. Currently, the UK vaccination strategy involves a 12-week gap 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 cancer, such as breast or prostate cancer, and hematologic (blood) cancers, such as leukemia. The prepress study has not yet been reviewed or published in pairs.
The researchers looked for 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 soared to 95% in the two weeks following the increase. Not enough booster shots were given to blood cancer patients to determine the response in this group.
The fact that antibody levels only increased to 43% in people with solid cancer and 8% in people with blood cancer five weeks after the first dose showed further evidence of the need for an increase. It was 100% in healthy volunteers.
“Our data provide the first real-world evidence of immune efficacy after a dose of Pfizer vaccine in immunocompromised patient populations. We show that after the first dose, most patients with hematologic and solid cancer remained immunologically unprotected until at least five weeks after the primary injection, but this poor effectiveness of a dose can be rescued with early reinforcement on day 21, “said Dr. Sheeba Irshad, a senior clinical professor at the School of Cancer and Pharmaceutical Sciences. led the investigation.
“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, such as social distancing. and protection when attending hospitals, even after vaccination, “Irshad added in a statement.
Stephen Evans, a professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine, stressed some limitations.
“The change in UK policy on delaying a second dose of vaccine allowed the authors to make some comparisons between those who received a second dose within 21 days and those who did not. they have provided data on those who received a second 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 both cancer and non-cancer patients,” he added.
“All of these findings are consistent with our understanding of immune system function in cancer patients,” said Shoba Amarnath, a researcher at the University of Newcastle at the University of Newcastle Cancer Center. “We know that the immune system of cancer patients is compromised compared to healthy controls. Therefore, a second vaccine boost prepares the deregulated immune system to function as efficiently as healthy controls.
“The study data support the notion that in solid cancer patients a considerable delay in the second dose will extend the period in which cancer patients are at risk for SARS-CoV-2 infection.”