Data from the world’s first reported trial has shown that more than half of cancer patients are left with little protection against the Covid-19 virus after receiving a single dose of the vaccine.
The study examined the level of immune protection after the Pfizer BioNTech vaccine was given to cancer patients, and it found that anti-SARS-CoV-2 antibody responses at week three, following the first dose, were only 39 per cent and 13 per cent in the solid and haematological cancers, compared to 97 per cent in those without cancer.
The preprint study also reports that following the second dose of the vaccine, given three weeks after the first dose, the immune response improved significantly for solid cancer patients, with 95 per cent of them showing detectable antibodies to the virus within just two weeks.
However, those who did not get the vaccine boost at three weeks did not see any real improvement, with only 43 per cent of solid cancer patients, and eight per cent of blood cancer patients, developing antibodies to the Pfizer vaccine at five weeks - compared to the 100 per cent of healthy controls.
‘12 week vaccine gap could leave cancer patients vulnerable’
The study says: “The evidence of vaccine responses in cancer patients shows that a gap of 12 weeks between doses of the Pfizer/BioNTech vaccine could leave many cancer patients vulnerable to serious Covid-19.”
The study was conducted by the King's College London and Francis Crick Institute research team, and as a result of the findings, the study’s senior authors believe that the Government should re-evaluate its policy for the dosing interval for all cancer patients.
Currently, the UK government placed more priority on giving as many people as possible one dose, rather than holding back vaccines to administer two doses in the recommended three week time frame.
The gap between the first and second jabs were therefore extended from three to 12 weeks.
‘Urgent review of the vaccine strategy’
Dr Sheeba Irshad, a senior clinical lecturer from the School of Cancer & Pharmaceutical Sciences, said: “Our data provides the first real-world evidence of immune efficacy following one dose of the Pfizer vaccine in immunocompromised patient populations.
“We show that following the first dose, most solid and haematological cancer patients remained immunologically unprotected up until at least five weeks following primary injection; but this poor one dose efficacy can be rescued with an early booster at day 21.
“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 distancing and shielding when attending hospitals, even after vaccination.”
‘Cancer patients should be intensively monitored’
Professor Adrian Hayday from King’s College London and The Francis Crick Institute said: “The vaccine is very impressive in its impact on healthy individuals and our study shows that it can clearly bring immense benefit to cancer patients too, but in most cases this is only after boosting.
“Cancer patients should be vaccinated and boosted quickly and their responses, particularly those of blood cancer patients, should be intensively monitored so that those who mix with family, friends and carers can be confident of their environment.
“These insights were only gained by way of truly intensive, selfless commitment of many young research fellows working together as a team. In making that commitment we have been brilliantly supported by our host institutions.”
‘Little protection against the virus’
Dr Simon Vincent, Director of Research, Support and Influencing at Breast Cancer Now, who supported the study, said: “For people with breast cancer, having certain treatments can increase their risk of contracting coronavirus, and of becoming seriously ill if they do get it, making it critical their needs are accounted for by the government’s vaccination strategy.
“Worryingly, this study suggests that people affected by cancer, including breast cancer, get little protection against the virus when they only receive a single dose of the Pfizer COVID-19 vaccine, and then do not receive their vaccine boost in the following three weeks. In contrast, the study identifies that when patients received a second dose of the vaccine within three weeks, they had significantly improved immune response and protection against coronavirus.
“In light of these findings we are calling on the Joint Committee on Vaccination and Immunisation to urgently review the evidence presented in this study, and to consider adapting its strategy to ensure that people who may benefit from this approach, including those with breast cancer, receive both the first and second dose of the Pfizer COVID-19 vaccine within a three week timeframe to minimise their risk of both contracting and becoming seriously ill with coronavirus.”