Experimental experiments in the UK with the Covid vaccine mix

LONDON – A trial is being launched in the UK to explore whether the use of different Covid-19 vaccines for the first and second doses works in an attempt to make vaccination programs across the country more flexible.

The trial, conducted by the University of Oxford and conducted by the National Immunization Schedule Assessment Consortium, will assess the feasibility of using a different vaccine for the initial “primary” vaccination for the follow-up “booster” vaccination.

The study is expected to help policy makers understand whether mixing Covid vaccines can be a viable route to increase the flexibility of vaccination programs and whether it can even provide better protection.

“If we show that these vaccines can be used interchangeably on the same schedule, this will greatly increase the flexibility of vaccine administration and could provide clues on how to increase the breadth of protection against new strains of the virus,” Matthew Snape, lead investigator on the trial and associate professor of pediatrics and vaccinology at Oxford University, he said on Thursday.

The trial, which is formally known as the “COVID-19 Heterologous Prime Boost study”, but has been dubbed the “Com-Cov” study, will recruit over 800 volunteers aged 50 or over in England to assess the four different combinations of cousins ​​and booster vaccination.

He will test a first dose of the Oxford-AstraZeneca vaccine followed by booster with the Pfizer-BioNTech vaccine or an additional dose of the Oxford-AstraZeneca vaccine. The research will also analyze a first dose of the Pfizer-BioNTech vaccine followed by booster with the Oxford-AstraZeneca vaccine or an additional dose of the Pfizer-BioNTech vaccine.

These will be evaluated in two different dosing schedules: at an interval of four weeks to give an early provisional data reading, and at an interval of 12 weeks. This latter dosage interval is the UK’s current vaccination policy: a delay in the second dose means that more people can receive their first vaccines earlier amid a restricted supply of vaccines.

Although the policy was considered controversial, with some experts concerned that it might make vaccines in use in the UK less effective; so far, only candidates from the University of Oxford-AstraZeneca and Pfizer-BioNTech are in use, with the Modern dose set to be added to the vaccine basket in use in late spring.

However, the University of Oxford published a study on Wednesday in which it showed that a 12-week delay between the first and the second dose of the AstraZeneca jab increases the vaccine’s effectiveness.

The researchers found that the injection was 76% effective in preventing symptomatic infection for three months after a single dose, and that the effectiveness rate increased to 82.4% when there was an interval of at least 12 weeks before the second dose. When the second dose was administered less than six weeks after the first, the efficacy rate was 54.9%.

In the latest “Com-Cov” study, researchers will collect blood samples from trial volunteers and monitor the impact of different dosing regimens on the participants’ immune responses, as well as looking for any additional adverse reactions to the new vaccine combinations.

The study will last 13 months and was supported by £ 7 million ($ 9.5 million) of government funding from Vaccines Taskforce, which was created by the UK last April to coordinate research and production efforts for a coronavirus vaccine .

Professor Snape said the study was “tremendously exciting”, before adding that “it will provide vital information for the launch of vaccines in the UK and around the world”.

The richest countries are struggling to vaccinate as many people as possible as national roadblocks, with the aim of limiting the spread of infections and preventing hospitals from being invaded, damaging economies.

The UK has been hit hard by the pandemic and has seen an increase in cases in the winter, aided by a more virulent variant of the virus that emerged in southeastern England which has now become a dominant strain in the country.

The UK has the fourth highest number of cases in the world today, with more than 3.8 million confirmed infections, according to a Johns Hopkins University count, and recorded 109,547 deaths.

The UK government was quick to pre-order coronavirus vaccines from a variety of manufacturers early last year and approve vaccines currently in use. Its vaccination program was widely praised for its agility and reach, and its goal is to have vaccinated 15 million people in its four priority groups, including health and care professionals, the elderly and people over 70 and anyone considered extremely vulnerable. clinic by mid-February.

The latest government data on Wednesday show that just over 10 million people received the first dose of the vaccine and just under 500,000 also received the second dose. The Oxford-AstraZeneca vaccine, which is produced in Britain, forms the bulk of the UK’s vaccination program.

The deputy chief medical officer and senior officer for the study, Professor Jonathan Van-Tam, said the research may even show that alternating vaccines can increase the level of antibodies needed to fight potential Covid-19 infection.

“It is also possible that when combining vaccines, the immune response can be increased, giving even higher levels of antibodies that last longer; unless this is evaluated in a clinical trial, we simply will not know. This study will give us a better view of how we can use vaccines to stay on top of this nasty disease, “he said.

UK vaccine minister Nadhim Zahawi told the BBC on Thursday that, for now, the country’s vaccination program will continue normally: “At the moment, we will not change anything,” Zahawi told the ‘Today’ program.

“If you received a Pfizer BioNTech vaccine for your first dose, you will have a Pfizer BioNTech vaccine for your second dose. If you took Oxford-AstraZeneca, you will have Oxford-AstraZeneca for your second dose.”