COVID-19: Pfizer jab produces less antibodies against Delta mutant, reveals Lancet Study

People inoculated using Pfizer/BioNTech jabs are likely to have five times lower level of neutralizing antibodies against the delta variant of coronavirus- which was first identified in India- compared to the original strain, a study published in The Lancet has disclosed. Additionally, it also stressed that the level of these antibodies is lower with this increasing age and decline over time. The study, conducted by researchers from Francis Crick Institute, directly testifies the need to reduce the gap between two doses of the vaccine.

"Increased age & time since 2nd dose correlated with reduced virus neutralisation across all strains tested. Not a surprise, but given low starting titres vs B.1.617.2, more of a concern to see neutralisation “dropping off”, significantly. Boosters more likely to be needed," Virologist David LV Bauer said in a statement. 

For the purpose of the study, researchers tested the ability of neutralizing antibodies to block entry of coronavirus into human cells. They conducted the test on people who had received two doses of Pfizer/BioNTech vaccine and against five different strains of COVID including the Delta and Beta mutation. In the aftermath, they discovered that the level of these antibodies was five-time lower when it came to the B.1.617.2 variant as compared to the original strain. This antibody response was even lower in people who had only received one dose.

Credits: David LV Bauer/The Crick/Twitter

Single Dose and Delta Variant

According to the researchers, 79 per cent of people who had received a single dose of  Pfizer vaccine - had a quantifiable neutralising antibody response against the original strain. However, it dropped to 50 per cent for B.1.1.7, 32 per cent for B.1.617.2 and 25 per cent for B.1.351 or Beta variant first discovered in South Africa. They also discovered that the anti-body level further lowered with age, regardless of the mutation. However, no link was found between antibody levels and BMI or gender.

"To maximise population coverage, the UK delayed 2nd dose from 3 weeks to ~12 weeks in early 2021. Was a good strategy vs. B.1.1.7, but single-dose vaccine recipients have significantly less ability to neutralise B.1.617.2 -- so strategy now more complicated," Virologist David LV Bauer said implying the need for the British government to reduce gap between two doses, 

Image: AP