Mucosal antibodies raised in the airways reduce COVID-19 reinfection by 55%

One of the biggest questions throughout the Covid-19 pandemic was reinfected. What is the probability? Will a reinfection be more or less severe than the first infection? How will the emergence of new variants affect reinfection rates?

A new study has found that contracting the Omicron The COVID-19 variant generated long-lasting mucosal antibodies that significantly reduce the risk of reinfection.

Mucosal immunity is known to protect against other respiratory infections. The to studyPosted in The Lancet Infectious Diseasesexamined how high levels of mucosal immunoglobulin-A (M-IgA) antibodies protect against COVID-19 reinfection.

“Antibodies in the blood protect against serious disease,” said Charlotte Thålin, MD, associate professor in the Department of Clinical Sciences at Danderyd Hospital and lead author of the study. “But if we aim to limit infection, viral transmission, and the emergence of new SARS-CoV-2 variants, we need to build our immunity at the mucosal surface, which is the viral entry point.

Investigators recruited 2,149 healthcare workers from Danderyd Hospital in Sweden. Since the spring of 2022, study participants’ immune responses to COVID-19 have been monitored via regular blood tests and respiratory screenings.

A substudy, conducted in January and February 2022, looked at 338 triple-vaccinated healthcare workers (2 doses of a primary vaccine Covid-19 vaccine series and 1 booster dose). The study found that participants with high mucosal IgA antibodies in their airways had half the risk of Omicron infection, compared to those with little or no antibodies in their airways.

High concentrations of SARS-CoV-2 WT spike immunoglobulin-A (M-IgA) from the nasal mucosa have already been shown to be effective against Omicron infection over a 4-week study period. With this research, investigators confirmed that patients with M-IgA concentrations of at least the 75th percentile at enrollment had a 55% reduced risk of symptomatic infectious breakthrough BA.1, BA.2, or BA .5 over an 8-month follow-up. -up period.

Even a mild infection with Omicron resulted in a more than 40-fold increase in M-IgA antibodies, findings that pave the way for more research into the protection afforded by a durable mucosal IgA antibody response in the airways.

“The hope is that a nasal vaccine can generate mucosal immune responses similar to those seen after infection, and thus block the chain of transmission,” Thålin said.