CDC confirms additional swine flu cases in the United States

As the confirmed cases of swine influenza A continue to climb, CDC and WHO officials said their primary efforts are now focusing on mitigation. Meanwhile, the Obama administration has asked Congress for $1.5 billion to fight the virus.

Richard Besser, MD, acting director of the CDC, said U.S. health officials are looking “intently” at growing a seed stock of this particular virus to create a vaccine. He also said officials at the CDC have shipped antivirals, gowns and masks to all states that have requested them. They are also shipping rapid detection tests so that confirmation of individual cases can be done on the state level.

Health officials are also using other forms of communication, including social media like Twitter, to communicate with the public about the virus.

At least 113 cases have been confirmed worldwide, including 64 in the United States, 19 in Mexico — the virus is suspected in dozens other fatalities in Mexico — six in Canada, 11 in New Zealand, one in Israel and two each in Spain and the United Kingdom. Of the U.S. cases, 45 are in New York City, 10 are in California, six are in Texas, one is in Ohio, and two are in Kansas, according to Besser.

Although most of the confirmed cases in the United States have been mild, Besser said five people in Texas and California have been hospitalized. The median age of most of the confirmed cases in the United States is 16, with ages ranging from 7 to 54. The earliest confirmed case in the United States presented March 28, and the most recent confirmed case presented to their health care provider April 24.

The rising number of confirmed cases globally prompted WHO officials to raise the level of influenza pandemic alertness from phase 3 to phase 4, which indicates that the likelihood of a pandemic has increased, but not that a pandemic is inevitable.

WHO officials said their decision was based primarily on data demonstrating human-to-human transmission and the ability of the virus to cause community-level outbreaks. However, Besser said that “regardless of label,” their focus remains the same: to look at methods to prevent spread, including emphasizing contact precautions, distributing treatment information as quickly as possible and revving up vaccine production.

Besser called on everyone to take contact precautions like handwashing, use of alcohol based sanitizer gels, covering coughs with arms or shoulders and encouraging “home isolation practices,” which, simply put, means staying home from school or work when a person feels sick.

CDC researchers are also working with officials from the Infectious Diseases Society of America and the Association of Professionals in Infection Control to develop guidance for treating individuals who have swine influenza.

According to its website, the CDC is recommending empiric antiviral treatment with zanamivir or oseltamivir be considered for confirmed, probable or suspected cases of swine influenza A (H1N1) virus infection as soon as possible after symptom onset.

Also, Besser said that health officials are in active discussions about vaccine preparations. Two types would be under consideration – either incorporating another protective strain of flu to the already-in-production seasonal flu vaccine, or a monovalent vaccine that would protect against this particular strain and would not affect current production activities. At this point the seed stock has not been shipped to any vaccine manufacturers, Besser said.

Kathryn Edwards, MD, of the Vanderbilt Vaccine Research Program said it is difficult to predict which vaccine strategy would be the most expedient.

“We’re likely to see vaccines coming down the pike very quickly that will need to be evaluated in healthy adults and studies obviously will need to be done fairly quickly in adolescents and children as well,” Edwards said. “It’s hard to know logistically which approach (a quadrivalent or monovalent) would be easier.” – Colleen Zacharyczuk