Public Health

Trials mixing Covid vaccines within the UK

Empty vials containing the Pfizer COVID-19 vaccine are seen at a drive-through vaccination facility operated by the Lake County Health Department in Groveland, Florida on January 28, 2021.

Paul Hennessy | NurPhoto | Getty Images

LONDON – A study is being launched in the UK to see if using different Covid-19 vaccines for first and second dose will help make nationwide immunization programs more flexible.

The study, led by Oxford University and conducted by the National Immunization Schedule Evaluation Consortium, will assess the feasibility of using a vaccine for the initial “prime” vaccination other than the subsequent “booster” vaccination.

It is hoped that the study will help policymakers understand whether mixing different Covid vaccines could be a viable way to increase the flexibility of vaccination programs, and whether it could even offer better protection.

“If we show that these vaccines can be used interchangeably on the same schedule, it will greatly increase the flexibility of vaccine delivery and could provide guidance on how protection against new strains of the virus can be enhanced,” said Matthew Snape, chief investigator of the process and associate Professor of Pediatrics and Vaccine at Oxford University said Thursday.

Officially known as the “COVID-19 Heterologous Prime Boost” study but dubbed the “Com-Cov” study, the study will recruit over 800 volunteers aged 50 and over in England to study the four different combinations of Prime and to evaluate booster vaccination.

A first dose of the Oxford AstraZeneca vaccine will be tested, followed by a booster with either the Pfizer BioNTech vaccine or another dose of the Oxford AstraZeneca vaccine. Research will also look at a first dose of the Pfizer BioNTech vaccine, followed by a booster with either the Oxford AstraZeneca vaccine or another dose of the Pfizer BioNTech vaccine. The British government has called the process a “world first”.

These are evaluated in two different dosing schedules: at an interval of four weeks to allow early intermediate reading of the data, and at an interval of 12 weeks. This latter dose interval is the current UK vaccination policy: delaying the second dose means that more people can get their first vaccines sooner with a shortage of vaccinations.

Although the policy has been viewed as controversial, some experts fear that it could make vaccines used in the UK less effective. So far only the candidates from the University of Oxford-AstraZeneca and Pfizer-BioNTech are used. The Moderna shot is due to be added to the vaccine basket later this spring.

However, Oxford University published a study on Wednesday that showed that a 12 week delay between the first and second dose of the AstraZeneca sting increased the vaccine’s effectiveness.

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

How the Com-Cov study will work

In the latest “Com-Cov” study, researchers will collect blood samples from volunteers from the study and monitor the effects of various dosage regimens on participants’ immune responses, as well as looking for additional side effects for the new vaccine combinations.

The study will last 13 months and was funded by the Vaccines Taskforce, established last April by the UK to coordinate efforts to research and manufacture a coronavirus vaccine, with £ 7 million of government funding (9, USD 5 million).

Professor Snape said the study was “tremendously exciting” before adding that “it will provide information that is critical to the launch of vaccines in the UK and globally”.

The richer countries are making every effort to vaccinate as many people as possible to limit the spread of infections and prevent hospitals from being overrun, which harms the economy.

Britain was hit hard by the pandemic, with cases spiking over the winter, aided by a more virulent variant of the virus that has emerged in south-east England and has now become a dominant strain in the country.

The UK currently has the fourth highest number of cases in the world with over 3.8 million confirmed infections. This comes from a record by Johns Hopkins University and recorded 109,547 deaths.

The UK government was quick to pre-order coronavirus vaccines from various manufacturers early last year and approve the vaccines currently in use. The vaccination program has been widely praised for its agility and range. The aim is to vaccinate 15 million people across the four top priority groups, including health and care workers, the elderly and the over 70s, and those who are considered to be extremely clinically at risk by mid-February.

The latest government data from Wednesday shows that just over 10 million people have received their first dose of vaccine and nearly 500,000 have received a second dose. The UK-made Oxford-AstraZeneca vaccine makes up the bulk of the UK vaccination program.

Professor Jonathan Van-Tam, deputy chief medical officer and senior responsible officer for the study, said the research may even show that alternating vaccines could increase the amount of antibodies needed to fight a possible Covid-19 infection.

“It’s even possible that the combination of vaccines may improve the immune response, resulting in even higher antibody levels that last longer. If this isn’t evaluated in a clinical trial, we just don’t know. This study will give us a better one Provide insight into how We can use vaccines to keep abreast of this dire disease, “he said.

The British vaccination minister Nadhim Zahawi told the BBC on Thursday that the country’s vaccination program will continue as usual for the time being: “At the moment we are not going to change anything,” Zahawi told the “Today” program.

“If you got a Pfizer BioNTech vaccine for your first dose, you got a Pfizer BioNTech vaccine for your second. If you had Oxford-AstraZeneca, you got Oxford-AstraZeneca for your second dose.”

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