Against twenty strains

Universal flu vaccine has been tested on animals

Sergey Vasiliev, Naked Science

American developers have received an RNA vaccine containing fragments of the genome of all common variants of the influenza virus. The new drug has demonstrated high efficacy in experiments on mice and ferrets, causing a good immune response and protecting them from infection with many varieties of both types of influenza virus. This is described in an article published in the journal Science (Arevalo et al., A multivalent nucleoside-modified mRNA vaccine against all known influenza virus subtypes).

Influenza viruses are divided into four genera, but the vast majority of human cases are associated with two — influenza type A and B. Within each of them, several serotypes are distinguished, and new strains appear every now and then within the serotypes themselves. This virus is characterized by very high variability, due to which new strains are constantly emerging, and vaccines quickly lose their effectiveness. Every year, doctors have to predict which of the new strains will cause another pandemic, and each time develop a new vaccine in advance to protect against it. Sometimes these forecasts do not come true, leading to the loss of huge resources and mass morbidity.

The solution to these problems can be a universal vaccine that can protect against many varieties of the flu virus. The team of Scott Hensley from the University of Pennsylvania is engaged in the creation of such a drug. Unlike most of Moderna's colleagues, they use a new technology of RNA vaccines, which became famous during the Covid-19 pandemic thanks to the successful developments of Moderna and the consortium of Pfizer and BioNTech.

Unlike traditional vaccines, which contain inactivated particles of the original virus or parts of its proteins, RNA vaccines include fragments of the viral genome in the form of a matrix RNA (mRNA) protected by a lipid envelope. Hensley and his colleagues managed to put "samples" from all 20 common serotypes of influenza virus types A and B. Theoretically, other varieties are possible, but the vaccine contains key variants.

The effectiveness of the drug was demonstrated in tests on mice: scientists have shown that animals produce antibodies to all 20 serotypes and their level remains stable for up to four months. Similar results were obtained on ferrets — popular model organisms in flu studies.

In other experiments, mice were divided into two groups, one of which received a vaccine, and the second — a similar drug- a "dummy". A month after vaccination, the animals were infected with influenza viruses that carried proteins similar to those encoded in the RNA vaccine or not too similar to it. The mice that received the vaccine coped with the first variant of the virus in 100 percent of cases, with the second — in 80 percent. Rodents who received a "dummy" always died. This suggests that the drug provides excellent protection from the serotypes contained in it, but reduced protection from new ones.

Portal "Eternal youth" http://vechnayamolodost.ru