blues flu vaccines. A new study says that live vaccines against influenza may increase susceptibility to these bacterial infections.
US Navy
influenza vaccines save millions of lives worldwide each year, but even heroes have their faults. A vaccine against influenza live attenuated, which contains weakened versions of the flu virus, the mouse makes it more vulnerable to bacterial infections in the nasal passages. The vaccine used in the study is similar to FluMist, including 13 million doses have been distributed in the United States this year. The work helps explain why runny nose were occasional aftereffect of FluMist in clinical trials.
"This study is an easy target for the anti-vaccine movement, but our findings should not be a concerned parent less likely to vaccinate their children," says Michael Mina, a virologist at Emory University in Atlanta , who led the research.
in the early days of getting the flu, a person becomes susceptible to opportunistic bacteria. Microbes like Streptococcus pneumoniae and Staphylococcus aureus that cause strep and staph throat infections, respectively, pounce on the exhausted immune system, causing secondary disease.
Mina wondered if vaccines against influenza attenuated could do the same. Some tests FluMist clinics, for example, recorded a slight increase in runny nose in children aged between 6 months and 5 years, a week after they got the vaccine. But no study had tried to understand what could be the cause of the side effect of studying in an animal model.
Mina and his colleagues mutated the H3N2 flu virus to mimic the weakened strain included in the vaccine FluMist. The mice then received this prototype vaccine or placebo either before or after being exposed to S. pneumoniae or S. aureus .
Both bacteria thrived after mice were vaccinated, but only in their nasal passages and upper respiratory tract, reports the Mina team in MBIO . Although similar infections can cause a runny nose in humans, they are much less dangerous staph infections and streptococci in the lungs and lower respiratory tract. In fact, no infection at all transpired in the lower respiratory tract of the vaccinated mice, which explains why zero rodents experienced a serious illness or died after bacterial exposure.
Although the findings are valid in humans, a slight increase in the risk of nasal discharge should not prevent anyone from getting a vaccine against influenza, said Mina. Overall, get vaccinated effectively reduces the risk of bacterial infection by preventing influenza and therefore the host of possible secondary infections.
And at the end of the day, this is only a mouse model, says Vincent Racaniello, a microbiologist at Columbia University. Still, he says, it raises a question about this mystifying vaccine: "When you Misdirect the immune response to a virus, why the bacteria take over?"
Then Mina will search for human tendencies heading towards Bangladesh, where large-scale trials of FluMist in children are underway. It will collect nasal swabs of children vaccinated to determine if the reasons for the mouse model are true. Dhaka a city with the population density can attend a slight increase in bacterial infections during mass vaccinations, he said.
According to Mina, some scientists in the field of the thought of his study should not be published because it casts a negative light on vaccines, but this research benefits ultimately the public, says Peter Palese, chairman of microbiology at the medical school Icahn Mount Sinai in New York City. "Vaccines are still the best ways to fight against the flu and many other diseases. Mice are not men, but it is important to learn about possible complications. "
0 Komentar