Many people struggle with the constant change in the flu vaccine, as the influenza viruses mutate rapidly, necessitating the reformulation of vaccines. But what if there were a flu vaccine that could be taken once and protect against currently circulating strains as well as all future variants?
The influenza virus continuously swaps out its genes, leading to the emergence of viral variants that evade both natural and medical immunity. This mutation process, known as antigenic drift, can occur within six to nine months, prompting medical authorities to frequently update the flu vaccine.
Recently, however, scientists seem closer to finding a solution to this problem by producing a vaccine that targets a conserved part of the virus. Traditionally, flu vaccines are manufactured to attack hemagglutinin, the proteins that are prevalent on the surface of influenza viruses. These proteins help the influenza virus bind to healthy cells before invading and taking over their internal machinery to reproduce and spread.
Current vaccines are made with a weakened version of hemagglutinin so that the immune system recognizes it as foreign and produces the necessary antibodies to combat influenza. Antibodies typically attach to the "head" of the hemagglutinin protein, obstructing the virus's attempts to bind to healthy cells. This part of the protein protrudes from the virus surface and is an easy target for antibodies; however, it is also the most variable part.
Professor Peter Openshaw, an immunologist at Imperial College London, explains that hemagglutinin is crucial for how the influenza virus attaches to and enters cells. He adds, "Almost all significant genetic variations that occur in the influenza virus happen at the globular head of this protein, and once these mutations occur, the antibodies triggered by the vaccine are largely ineffective against the infection."
One way to circumvent this issue is to create vaccines that do not target the head of the protein but rather its "stem," where the hemagglutinin protein meets the main body of the virus. Mutations occur here much less frequently than at the head, as the genetic material found in this section is essential for the virus's survival. Moreover, the genetic makeup of the hemagglutinin stem region is almost identical across all influenza strains, making it an ideal target for a universal vaccine.
Scientists hope that such a vaccine would activate the immune system to produce antibodies that attack the stem area of the virus instead of the head. However, this is not a simple task, as previous attempts to produce a flu vaccine targeting the stem of the virus have encountered setbacks, according to the Daily Mail.
