The immune system has several ways to protect us against viruses. One of them is the production of specific antibodies by B Lymphocytes (Plasmocytes) against epitopes of the virus–acquired immunity. Some memory B lymphocytes that produce these antibodies can be selected and reserved to defend against a new attack by the same virus. Another type of defense involves cytotoxic T lymphocytes, which destroy infected cells, preventing the virus from replicating.
This immunity can be permanent, long-term, that is, it can last for years, and it is with this objective that vaccine producers act, trying to obtain this long-term defense response. Unfortunately, this is not always possible, as is the case with HIV. To give a safe response to the population, researchers need to monitor antibody levels longer to find out.
It is also important to monitor whether these antibodies will remain in low concentration – as is common with viral infections – or rapidly decline. When researchers followed COVID-19 patients this year, they found that the number of antibodies peaked in the days following the onset of symptoms and then began to decline. In several of these patients, the antibodies were virtually undetectable by about three months. To determine how significant this decline might be, researchers still need to know how much antibody is needed to successfully prevent infection.
If immunity to the virus lasts for less than a year, for example, like other circulating human coronaviruses, there could be yearly increases in infections through 2025 and beyond. But, as was said at the beginning, the production of antibodies is not the only form of immune protection; there is also innate immunity, which may be responsible for the differences in the severity of infections.
In the meantime, we need to keep the innate defenses activated. For this, we have the M8 immunomodulatory complex. As observed over many years of research, M8 rapidly activates macrophages and other defense cells, even without direct contact, but also through the production of small molecules such as nitric oxide and cytokines.