Pfizer vaccine generates five times fewer antibodies against Delta (Indian) variant

The Pfizer Covid-19 vaccine is significantly less effective at generating antibodies to the Delta variant of Coronavirus first found in India.

A new study from the Francis Crick Institute revealed that older people are more at risk with levels of antibodies getting lower with increasing age.

The results of the study showed strong evidence for providing a third booster jab for vulnerable people in the autumn and reducing the gap between the first and second dose of the jab to provide stronger immunity.

In the UK, experts are also calling for lockdown easing to be delayed by a few weeks to ensure that more people have had two doses by the time restrictions are more widely lifted.

Work is now being carried out by the same researchers on the AstraZeneca vaccine to find out if the same is true of the Oxford-created UK jab.

Dr Rosalind Eggo, a member of the Scientific Pandemic Influenza Group on Modelling (Spi-M) Government advisory panel, said with “very early evidence” showing that the current vaccines on offer “don’t work quite as well against the Delta variant”, it was important to increase the rate of second jabs.

Getting those second doses up, pushing that number up as high as possible is really important.
she told BBC’s Newsnight.

Pushing back by a fortnight the plans to lift all restrictions in order to allow more adults to be fully vaccinated could see so-called “freedom day” in England delayed until July 5. In Wales, Mark Drakeford has taken a slightly slower approach and is still planning to significantly relax restrictions on people meeting indoors from June 21 with further easing slated for later in the summer.

The UK on Friday recorded its highest number of new confirmed coronavirus cases – 6,238 – since late March, according to official figures.

Figures from the Office for National Statistics (ONS) also suggested the number of people who had the virus in England has increased by around three quarters in a week, taking it to its highest tally since mid-April, with the R value between 1 and 1.2.

In his Friday briefing, First Minister Mark Drakeford said that despite Wales having a significantly lower infection rate than England or Scotland, at just 8.2 cases for every 100,000 people in the last week – compared to over 30 in England – Wales was not immune from the threat of the Delta variant.

If that pattern continues, we will not be immune from it here in Wales. Already we have identified 97 cases in Wales and there will be more.

The research from the Francis Crick Institute and the National Institute for Health Research (NIHR) UCLH Biomedical Research Centre, was published as a Research letter in The Lancet.

The researchers said it was the largest study published to date investigating vaccine-induced antibody neutralising capacity against the newest variants of concern in healthy adults.

Healthcare workers and staff from the institutions have been donating regular blood and swab samples so that researchers can track changing risk of infection and response to vaccination.

The academics studied antibodies in the blood of 250 healthy people who received either one or two doses of the Pfizer-BioNTech Covid-19 vaccine, up to three months after their first dose.

They tested five strains including the original Wuhan virus, the strain that became dominant in Europe last spring, the Kent variant (Alpha), South Africa variant (Beta) and Indian variant (Delta)

They found that in people who had been fully vaccinated with two doses of the Pfizer-BioNTech vaccine, levels of neutralising antibodies were more than five times lower against the B.1.617.2 (Delta) variant when compared to the original strain, upon which current vaccines are based.

Importantly, this antibody response was even lower in people who had only received one dose. After a single dose of Pfizer-BioNTech, 79% of people had a quantifiable neutralizing antibody response against the original strain, but this fell to 50% for B.1.1.7, 32% for B.1.617.2 and 25% for B.1.351.

While antibody levels decreased with age against all variants, no correlation was observed for sex or BMI.

Emma Wall, UCLH Infectious Diseases consultant and Senior Clinical Research Fellow for the Legacy study, said:

This virus will likely be around for some time to come, so we need to remain agile and vigilant. Our study is designed to be responsive to shifts in the pandemic so that we can quickly provide evidence on changing risk and protection.

The most important thing is to ensure that vaccine protection remains high enough to keep as many people out of hospital as possible. And our results suggest that the best way to do this is to quickly deliver second doses and provide boosters to those whose immunity may not be high enough against these new variants.

David LV Bauer, group leader of the Crick’s RNA Virus Replication Laboratory and member of the G2P-UK National Virology Consortium, said:

New variants occur naturally and those that have an advantage will spread. We now have the ability to quickly adapt our vaccination strategies to maximise protection where we know people are most vulnerable.

Keeping track of these evolutionary changes is essential for us to retain control over the pandemic and return to normality. This work is a powerful example of effective collaborations between NHS and academic colleagues, that can help us to navigate changes in this new phase of the pandemic.

Image By Irfan Khan / Los Angeles Times via Getty Images

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