Eideard

Every autumn, as predictably as falling leaves, flu season descends upon us. Every spring, just as predictably, the season comes to a close. This cyclical pattern, common in temperate regions, is well known, but the driving forces behind it have been in question.

Do existing strains die off each spring, only to be replaced each fall by new founding strains from other parts of the world, or does a “hidden chain of sickness” persist over the summer, seeding the next season’s epidemic?

A genetic analysis by University of Michigan postdoctoral fellow Trevor Bedford and colleagues at U-M, Howard Hughes Medical Institute and Florida State University reveals that in the United States, not all strains of influenza die off at the end of winter; some move southward to South America, and some migrate even farther.

“We found that although China and Southeast Asia play the largest role in the influenza A migration network, temperate regions — particularly the USA — also make important contributions,” Bedford said. Rather than dying off at the end of our flu season, many strains simply move on to more favorable environments.

Growing knowledge about patterns of flu migration eventually may make it possible to tailor vaccines to particular locations, Bedford said.

“We found, for instance, that South America gets almost all of its flu from North America. This would suggest that rather than giving South America the same vaccine that the rest of the world gets, you could construct a vaccine preferentially from the strains that were circulating in North America the previous season. As we gather more data from other regions, this could be done for the entire world.”

All the more reason to develop a universal flu vaccine – even if it needs to be tailored geographically.

Infants born to women who received influenza vaccine during pregnancy were hospitalized at a lower rate than infants born to unvaccinated mothers, according to preliminary results of an ongoing study by researchers at Yale School of Medicine…

Influenza is a major cause of serious respiratory disease in pregnant women and of hospitalization in infants. Although the flu vaccine is recommended for all pregnant women and children, no vaccine is approved for infants less than six months of age. Preventive strategies for this age group include general infection control and vaccination of those coming in close contact with them. Few studies have examined the effectiveness of the flu vaccine during pregnancy…

“We found that vaccinating mothers during pregnancy was 80 percent effective in preventing hospitalization due to influenza in their infants during the first year of life and 89 percent effective in preventing hospitalization in infants under six months of age,” said Marietta Vázquez, M.D..

“These results not only have a positive impact on the health of susceptible infants, but also may be very cost effective, as it involves one vaccine providing protection to two individuals,” Vázquez added. “The findings may also help establish public health policy, increase awareness of the importance of influenza vaccination during pregnancy, and even help to overcome barriers to vaccination.”

Bravo! I don’t know if I can take so much good news in such a short article.