Breakthrough COVID-19 infection induces strong antibody responses: Study

The findings were published in ‘Cell’, one of the scientific journals of Cell Press.

Alexandra Walls and David Wesler in the Department of Biochemistry at the University of Washington in Seattle led the project.

Characteristics of the Delta and Omicron coronaviruses include enhanced communicability and immune evasion even in non-immunologically nave individuals compared to the ancestral pandemic coronavirus.

These characteristics, and decreased immunity from vaccines, have resulted in successful infection in vaccinated individuals. For the most part, otherwise healthy people who were vaccinated against SARS-CoV-2 usually do not have severe symptoms if they contract the virus.

The researchers wanted to understand how catching the virus after vaccination had neutralizing antibodies, and to see how durable and widespread these responses were. His hope was that advancing such knowledge would help guide vaccination policies and epidemic mitigation strategies.

Through their project the researchers learned that the degree of antibody response depends on whether a person has had one, two, three, or four exposures to the spike protein through infection, vaccination, or a mixture of the two. The scientists also checked antibody responses in groups of individuals who were vaccinated after having COVID-19, those who had previously been vaccinated and experienced a successful infection, those who were only vaccinated, and Those who were amplified and therefore vaccinated three times.

In their study subjects, those who had completed a three-vaccination protocol, and who were vaccinated after recovery from COVID-19, and those with a successful infection following vaccination, had nearly comparable neutralizing antibody responses in terms of magnitude and breadth. launched. Their serum binding and antibody neutralizing responses to the spike protein in current pandemic coronavirus variants were much more potent and permanent than those who had received only two doses of the COVID-19 vaccine or had not been vaccinated for a previous infection.

This observation suggested that increased numbers of infections and exposure to SARS-CoV-2 antigens through vaccination or triple vaccination enhanced the quality of antibody responses.

The researchers also looked at how widespread the antibodies obtained could be. They investigated neutralizing anxiety of the different Omicron SARS-CoV-2 type, which currently accounts for the majority of cases in the United States. Their findings showed that increased individuals (or those who have had a mixture of infection and double vaccination) have neutralizing antibodies at similar levels to subjects who were twice vaccinated against the original parental strain. This suggested a large degree of immune evasion, but that vaccine boosters could help neutralize the antibody gap caused by Omicron.

A similar pattern appeared when looking outside the SARS-CoV-2 family, where repeated and multiple exposures improved an otherwise weak neutralizing antibody response to SARS-CoV. Finally, the authors did not identify an improvement in antibody binding to the common cold leading to coronavirus spike proteins such as OC43 or HKU1.

This suggested that repeated exposure to SARS-CoV-2 does not improve spike reactivity to more different coronaviruses. These findings supported the development of widespread sarbecovirus or coronavirus vaccines to be prepared in the event of a future spillover event.

The study groups included about 15 people who were hospitalized or had respiratory viral infections with ambulatory adults, or HAARVI, project at UW in Seattle. Led by UW Medicine infectious disease physician Helen Chu, HAARVI looked at recovered COVID-19 patients to study immune responses over time, understand the long-term consequences of infection, and compare immune responses to vaccines and natural infections. (ANI)