CDC calls H1N1 virus 'homogeneous,' anticipates vaccine development

ATLANTA The Centers for Disease Control and Prevention announced on Friday that scientists have determined that the various strains of novel H1N1 virus around the world are homogeneous — a factor that makes the development of a vaccine much easier.

“From our analysis, we have confirmed that the novel H1N1 virus likely originated from pigs, based on data that each of the genetic components of this virus are most closely related to corresponding influenza virus genes identified from swine influenza viruses,” commented Nancy Cox, director of the CDC’s influenza division, during a press call on Friday.

Referencing an article published Friday in the journal Science, Cox noted that the new H1N1 viruses are antigenically similar to each other. That is, they react to antibodies in a similar way. They’re rather homogeneous,” she said. “This makes our job of coming up with a reference candidate vaccine virus much, much easier. We see much less variation among these new H1N1 viruses than we do for typical, seasonal influenza viruses.”

Currently, the CDC is working on two vaccines for H1N1. One candidate vaccine virus was created by combining the genes of the novel H1N1 virus that are responsible for eliciting protection to influenza with other parts from other viruses that are needed for high growth in eggs. “That process is called reassortment,” commented Anne Schuchat, director of the CDC’s national center for immunization and respiratory diseases. Also, the CDC and the Federal Drug Administration have created a candidate virus using reverse genetics.

“Here at CDC, we’re performing analysis of the egg-derived and reverse genetics-derived candidate vaccine viruses to make sure that they are able to stimulate optimal immune responses, or that their ability to do that remains intact,” Schuchat said. “And after that work is done, suitable viruses will be sent out to manufacturers. We expect by the end of May that will happen so that they can begin work on developing candidate vaccine seed for production of pilot loss of vaccine.”

As of Monday at 11 a.m., there were 6,764 confirmed cases of H1N1 across 48 states, including 10 deaths. Schuchat estimated on Friday that there may be more than 100,000 active cases in the United States currently.