Two doses of COVID vaccines induce low antibody levels against Omicron: Oxford study

Researchers from the University of Oxford in the UK analyzed the effect of the Omicron version of anxiety on one of the immune responses triggered by vaccination.

The peer-reviewed study, to be posted Monday on preprint repository MedRxiv, used blood samples from individuals who had previously received two doses of AstraZeneca or Pfizer vaccines, and a live virus isolate.

Researchers have demonstrated a substantial reduction in neutralizing titres – a measure of the level of neutralizing antibodies produced in response to infection, or vaccination against COVID-19.

The results indicate that the Omicron variant has the potential to drive another wave of infection, which already involves vaccination, the researchers said.

However, they noted that there is no evidence of an increased likelihood of serious illness, hospitalization, or death in the vaccinated population.

These results are in line with recently published data from the UK Health Protection Agency showing a lower effectiveness of two doses of these vaccines against symptomatic disease caused by the Omicron variant compared to Delta.

However, this effectiveness was improved by the third dose of the vaccine, the researchers said.

Professor Gavin Scritten, Head of Medical Sciences, Oxford, said: “These data will help people develop vaccines and vaccination strategies, determine the routes to take to protect their populations, and deliver the message. press home that those who are offered a booster vaccination should take it.” Division, and lead author of the paper.

“While there is no evidence of an increased risk of serious illness, or death, from the virus among the vaccinated population, we should be cautious, as a higher number would still put a significant burden on health care systems,” Scritten said.

The researchers noted that these data are important but only part of the picture.

They only look at neutralizing antibodies after the second dose, but don’t tell us about cellular immunity, and that will also be tested using stored samples once the test becomes available, he said.

“Importantly, we have not yet assessed the effect of a ‘third dose’ booster, which we know significantly increases antibody concentrations, and it is likely that this will lead to a better potency against the body. omicron versionMatthew Snipe, a professor at the University of Oxford and a co-author of the study, said.

“Vaccination induces multiple arms of our immune system, including neutralizing antibodies and T-cells,” said Teresa Lambe, a professor at the University of Oxford and author of the paper.

“Real-world effectiveness data has shown us that vaccines continue with previous forms of concern to protect against serious disease. The best way forward in this pandemic is to get vaccines in arms,” ​​Lambe said.

This story has been published without modification in text from a wire agency feed. Only the title has been changed.