Our COVID-19 vaccine passed the first test with excellent results. They are working very well and are helping to slow the spread of diseases in countries where they are widely available. Now, scientists are turning to the following fundamental question: How long can they work so efficiently?
New research shows that people who are vaccinated after contracting COVID-19 may work for many years. The bone marrow of this population has powerful memory cells that can produce new antibodies when needed. Studies have shown that they are very effective and can even prevent virus variants. These people may not even need to boost injections for long-term protection. Michel Nussenzweig, an immunologist at Rockefeller University in New York, told the New York Times that security might differ for people who have been vaccinated but have never contracted COVID-19. The immune system responds to vaccines differently from natural infections, so even if they have solid and long-lasting protection against the original strain of coronavirus, they may need booster vaccines against these mutations. “This is something we will know soon,” Nussenzweig said. Fortunately, other research is ongoing to find out exactly what these potential drivers look like. Scientists are paying attention to the level of antibodies that someone needs to fight COVID-19.
This benchmark, called the immune-related factor of protection, will give you an idea of the safety threshold. If someone’s antibodies are below that threshold, they may again be more susceptible to infection. First, it provides scientists with a way to monitor the protection of people who have been vaccinated. They can see how long it takes for the antibody to drop below it and understand when people need booster injections. Antibodies naturally decline over time and are not the only protective measure (for example, those long-acting memory cells in the bone marrow are another). But they are early observations of how immunity may change.
Second, having a protection threshold opens up a shortcut to create the necessary enhanced injection against COVID-19 variants. The COVID-19 vaccine trial involves tens of thousands of people. They took several months to run because researchers needed to understand how often vaccinated and unvaccinated people got sick. However, once we know the immune response to prevent infection, we can try boosters in smaller populations. They are functionally identical vaccines with only minor adjustments. We already know that vaccines are safe, so all they have to do is to check whether the new version also pushes people’s immune systems to the edge.
Together, this research describes a way to protect people from COVID-19 in the future. It begins to alleviate concerns that the coronavirus protection will start to fade over time, putting communities at risk of outbreaks in the future. The virus is tricky, the variant is a curveball, but fortunately, the human immune system also has ammunition.