Scientists Find New Way to Predict COVID-19 Vaccine Efficacy
Scientists Find New Way to Predict COVID-19 Vaccine Efficacy | Photo credit: Pixabay & nbsp
Canberra: The early immune response in a person who has been vaccinated against COVID-19 can predict the level of protection they will have against the virus over time, according to an analysis by Australian mathematicians, clinicians and scientists published in the journal Nature Medicine. Researchers at the Kirby Institute at the University of New South Wales, the Peter Doherty Institute for Infection and Immunity and the University of Sydney have identified an “immune correlate” to vaccine protection. This has the potential to dramatically reduce development times for new vaccines, by measuring levels of neutralizing antibodies as a “ proxy ” for immune protection against COVID-19.
“Neutralizing antibodies are tiny Y-shaped proteins produced by our bodies in response to infection or vaccination. They bind to the virus, reducing its ability to infect,” says Dr Deborah Cromer of the Kirby Institute. “While we’ve known for some time that neutralizing antibodies are likely to be an essential part of our immune response to COVID-19, we don’t know how many antibodies you need for immunity. Our work is the strongest evidence to date to show that specific antibody levels result in high levels of protection against disease. “
Researchers analyzed data from seven COVID-19 vaccines to examine the correlation between the response measured soon after vaccination and protection. They then used statistical analysis to define the specific relationship between immune response and protection. Their analysis was remarkably precise and made it possible to predict the effectiveness of a new vaccine.
Dr Cromer said this discovery has the potential to change the way we conduct COVID-19 vaccine trials in the future.
“Antibody immunity levels are much easier to measure than directly measuring the effectiveness of vaccines over time. So, by measuring antibody levels across the range of new vaccine candidates during the early stages of clinical trials, we can better determine whether a vaccine should be used to prevent COVID -19. “
Another crucial application of this analysis is its ability to predict immunity over time. Researchers predict that immunity to COVID-19 resulting from vaccination will drop dramatically within a year, with the level of neutralizing antibodies in the blood decreasing in the first few months after infection or vaccination.
“Vaccination works very well to prevent both symptoms and serious illness in the short to medium term, but the effectiveness is expected to decrease in the first few months for most of these vaccines,” says Dr David Khoury, also of the Kirby Institute. “However, it is very important to understand the difference between immunity against infection and protection against the development of serious disease. Our study found that 6 times lower antibody level is needed to protect against disease. So even though our analysis predicts that we will begin to lose immunity to mild infection within the first year after vaccination, the protection against severe infection should last a long time, ”says Dr. Khoury.
“But ultimately, for optimal protection against moderate illness and transmission of COVID-19, these results suggest that we may be considering annual vaccine boosters, just like what we have with the flu shot. . “
A major global challenge is the evolution of the virus and the emergence of new variants. According to laboratory studies, there is growing concern that antibodies developed against dominant strains are less effective in neutralizing these new variants.
“An added benefit of our work is that it allows us to predict how well an immune response is protected against different variants,” says Professor Jamie Triccas of the Marie Bashir Institute at the University of Sydney and the Faculty. of medicine and health. “This analysis shows a very good correlation between the immune response – which is very easy to test and the effectiveness of a vaccine in preventing infections, which is incredibly difficult to test. This means that we can predict how well an immune response will be protective, be against different variants, without having to determine the efficacy against each variant in large and expensive clinical trials. “