Flu vaccine cleared of the virus

Flu is one of the most common infectious diseases in the world — about a billion people fall ill every year. Flu is also a frequent cause of death. During the 1918 pandemic (the “Spanish flu”) between 20 and 50 million people died from the disease (the 2009 flu pandemic, incidentally, was caused by a virus of the same A/H1N1 serotype). According to Medscape, an average of 20,000 people die of flu every year.

The most effective way to fight the disease is prevention, so vaccination is crucial in preventing epidemics. Vaccination introduces small components of the virus into the body, which triggers the immune system to produce antibodies. When the body then meets the infection it already has robust defenses.

Every year the WHO, tracking the epidemiological situation, recommends several virus strains for flu vaccination — because different strains cause flu each year (rapid mutation is a key feature of the flu virus and greatly complicates combating it). The US CDC recommends annual vaccination of everyone over 6 months old, especially those at risk of complications. In Russia mandatory vaccination is recommended only for at-risk groups — children and pregnant women, in whom the illness can cause complications for the fetus or pregnancy.

Classic flu vaccines contain small fragments of the virus — virions — capable of eliciting an immune response.

They are produced by cultivating the flu virus in chicken eggs. Different isolation and purification methods are then used. Some vaccines contain only a few surface proteins — hemagglutinin and neuraminidase, critical for the virus’s entry into the cell.

The new flu vaccine type also contains one of these surface proteins — hemagglutinin. But it is obtained by a fundamentally different mechanism.

Researchers isolated a set of enzymes that read DNA and synthesize proteins from insect viruses and had them synthesize hemagglutinin matching specific flu strains.

Note that with conventional vaccines the bulk of antibodies is also produced against hemagglutinin.

The vaccine’s efficacy was confirmed in a study of 2,300 people (with an equivalent control group). In about 44.6% of cases the vaccine was effective against all encountered flu strains. Side effects occasionally included headache, fatigue and pain at the injection site — similar to those with conventional flu vaccines.

“The main advantage of the new manufacturing method is speed — the new technology will allow very fast scale-up of vaccine production during a pandemic, because it does not require isolating the flu virus or chicken eggs,” said Karen Midthun, director of the FDA’s Center for Biologics Evaluation and Research.

Additionally, the product can be used to vaccinate people with egg allergies.

Source: Gazeta.ru