Minor flu strains pack bigger punch.

• Position: Pandemics - Brief article

Minor variants of flu strains, which typically are not targeted in vaccines, carry a bigger viral punch than previously realized, a team of scientists has found. Their research shows that these minor strains are transmitted along with the major strains and can replicate and elude immunizations.

"A flu virus infection is not a homogeneous mix of viruses, but, rather, a mix of strains that gets transmitted as a swarm in the population," explains Elodie Ghedin, professor in New York University's Department of Biology and College of Global Public Health. "Current vaccines target the dominant strains because they are the ones that seem to infect the largest number of individuals, but our findings reveal an ability of minor strains to elude these vaccines and spread the virus in ways not previously known."

It long has been known that the Influenza A virus is marked by a high level of genetic diversity. However, this knowledge largely stems from the dominant strain, which vaccines aim to...