British scientists are examining whether smaller doses of the Covid vaccine could be used as part of booster programs, with the hope that the approach could also increase vaccine supply across the world.
The use of so-called “split doses” has been proposed as a way to ensure that valuable supplies can immunize as many people as possible in areas of the world where there are shortages, while still providing high levels of protection. against the virus.
Several members of the Joint Committee on Immunization and Immunization (JCVI), which advises the UK government, are said to be interested in the idea. Lower doses of vaccines to control other diseases have been used in times of scarcity.
JCVI is expected to rule out an immediate booster vaccine program for all adults pending the emergence of new research, although the government is on the verge of providing follow-up injections for those most at risk and in need of treatment. ‘a strengthening of their immunity. . It could start as early as next month. Hospital admissions and deaths from the virus increased slightly over the past week, with around 100 deaths reported each day.
The effect of using lower doses in booster shots is one of the questions explored in an ongoing Cov-Boost trial supervised by Southampton University Hospital. It was funded by the government vaccine task force and the National Institute for Health Research.
His findings will inform JCVI’s decisions about a fall booster program, as well as data from other trials and studies. Researchers are looking at the safety and side effects of different doses, as it is possible that smaller amounts of the vaccine could stimulate immune responses while reducing the risk of side effects. Different vaccines might also behave in different ways.
Some epidemiologists would like more studies to be commissioned because of the possibility of helping the global vaccine supply. It is estimated that around 11 billion doses will be needed to fully immunize 70% of the world’s population. At the beginning of July, only 3.2 billion jabs had been administered. Researchers estimate that many of the world’s poorest will have to wait until 2023 for a vaccine.
Research on divided doses has already been done. An article edited by Professor Benjamin Cowling, an epidemiologist at the University of Hong Kong, recently argued that the use of lower doses “is a potential solution to this global vaccine shortage that has not received enough attention. and consideration ”. Some researchers have warned that the approach may lead to greater resistance to the vaccine, but that could be offset by fewer people infected.
David Hunter, professor of epidemiology and medicine at the University of Oxford, said the idea of reducing doses has been deployed in the fight against other diseases. “Further expanding the vaccine supply by administering lower doses of antigens has been a strategy used in emergencies when supplies of Ebola and polio vaccines were limited,” he said. . “The basic idea is to vaccinate more people with the same supply. The key question is whether for each individual the efficacy of the vaccine is reduced, and if so, by how much.
“It is plausible that the booster injections could be given at a lower dose than the first and second injections. Studies are underway for several Covid-19 vaccines to assess this. If a lower dose is found to decrease efficacy only slightly, then national regulators will need to consider the potential international benefits of increasing the number of injections available. It will be essential that this be done in a way that does not cause vaccine hesitation due to the perception that reduced dose injections are inferior. “
Professor Danny Altmann, an immunologist at Imperial College London, said the global shortage was more about distribution than supply. He added that it was possible to explore the dosage amounts.
“Vaccine dosing, like everything else over the past 18 months, has been about building the plane while we fly, so there is endless potential to be realized. [randomised controlled trials] review the maximization of dose distribution. This has been done extremely effectively to deal with the shortfall in the production of yellow fever vaccine doses. “
A spokesperson for the Department of Health and Welfare said a recall program was being prepared for Britain’s most vulnerable people. “Any recall program will be based on the final opinion of the independent JCVI. Until we receive independent advice from JCVI, no decision can be made on broader requirements for those receiving recall jabs.
“The UK is committed to supporting a global recovery from the Covid-19 pandemic and improving access to vaccines – and we will donate 100 million excess vaccine doses over the next year,” as well as supporting Covax to distribute 1.3 billion doses to 92 developing countries. ”