A new University of Michigan study found that COVID-19’s natural infection protected against reinfections when the delta or gamma variants prevailed.
The study was conducted in a Nicaraguan community and revealed that antibodies induced by infection protect against 69% infections and 79 percent protection against moderate or severe diseases. The second infection was less severe than the first.
The study is published as a preprint while it is undergoing peer review.
The course of the pandemic will be determined by the quality and longevity of the immunity that is provided by both natural infections and vaccination. We hope that having an immune correlate of the protection induced by infection and a better understanding of the severity of second-infections will inform vaccine policies and help guide targeting at-risk populations and other mitigation strategies.”
Hannah Maier, postdoctoral researcher associate at U-M’s Schools of Public Health and the principal author of this study.
Researchers utilized the ongoing prospective Household Influenza Cohort Study, Managua (Nicaragua) to conduct their research. It was established in 2017, the group was established to study the effects of influenza on households and was expanded in February 2020 to include the study of SARS-CoV-2 and its associated diseases. Participants are asked to visit the study center immediately they experience symptoms of sickness. They are then treated with primary health care.
Serology blood samples are collected annually in March-April and a second mid-year sample was collected for those who agreed to it in October 2020. A transmission study is nested within the study, where participants are monitored closely and tested regardless of symptoms after a SARS-CoV-2-related case is found in their home.
To test for SARS-CoV-2, researchers used real-time reverse-transcription polymerase chain reaction. They employed a method known as enzyme-linked immunosorbent assays, or “ELISAs” to determine antibodies levels.
Researchers discovered that 62% of the group were positive for SARS CoV-2 in March 2021, before the onset of a major second wave of COVID-19. Delta and Gamma variants prevailed. Researchers identified the necessary antibody levels to prevent disease, infection severe or moderate disease. The levels needed to guard against severe or moderate disease were lower than the levels needed to keep it from happening.
Aubree Gordon, senior author, stated that second infections are not as severe as the first, and are not as easy as they would have liked to be. She advised that vaccinations are required to lessen the effects of the SARS/CoV-2 pandemic.
When she was asked about the latest variations of the vaccine she responded that the SARS-CoV-2 pandemic is continuing in its second year and vaccine availability is restricted, especially in low- and middle-income countries.
“The emergence of variants is really stressing that vaccine equity is extremely important. We are all part of this, and we need to ensure that vaccines are accessible to those in low- and middle-income countries,” she stated.
She said that Omicron is a very complex product and there are many things we don’t know. “We believe that the risk of being protected will be lower than that we observed in this study.”
Gordon is an advisor to Janssen’s advisory board. The National Institute for Allergy and Infectious Diseases at National Institute of Health and Open Philanthropy support the work.
Content Source: https://www.news-medical.net/news/20211130/Natural-COVID-19-infection-offers-protection-from-gamma-and-delta-variants-of-SARS-CoV-2.aspx
