CDC held the first formal press briefing on April 23, 2009 to inform the media and guide the health care respond and the public with the rapidly changing situation and they have held almost 60 press briefings during the entire 2009 H1N1 response. On April 24, 2009, CDC uploaded complete gene sequences of the 2009 H1N1 virus in a publicly-accessible influenza database and updated reports on the outbreak also became available online in the MMWR. This helped scientists around the world to use the sequences for health research and comparison against influenza viruses collected other places.
The Director-General of WHO declared the 2009 H1N1 outbreak as a Public Health Emergency of International Concern on Saturday, April 25, 2009, under the rules of the International Health Regulations. They also suggested countries to increase surveillance for unusual occurrence of influenza-like infection and severe pneumonia. Then CDC confirmed two cases of 2009 H1N1 influenza infection in Kansas and another in Ohio shortly after April.
CDC’s Strategic National Stockpile (SNS) began releasing 25% of the supplies in the stockpile that is used to protect from and treat influenza to all states on April 26, 2009. This included 11 million antiviral drugs treatment and personal protective tools, which was over 39 million respiratory protection equipments such as masks and respirators, face shields, gowns and gloves; the amount distributed was based on each state’s population. By April 2009 the Federal Government had bought 50 million treatment of antiviral drugs, in particularly oseltamivir and zanamivir, as part of the nation’s pre-pandemic planning. The Emergency Use Authorizations (EUAs) used the products in a way different from what they were FDA-approved for. This includes:
oseltamivir is used to treat children younger than 1 year old by preventing influenza in children 3 months to 1 year old;
oseltamivir and zanamivir are used to treat patients who are symptomatic for more than two days before starting the treatment or for those who had complication of illness that requires hospitalization.
The WHO Director-General raised the level of influenza pandemic alert from phase 3 to phase 4 on April 27, due to the increasing reports of influenza-like-illness and deaths in Mexico. Hence CDC released a travel health warning stating that United States travelers should postpone all non-essential travel to Mexico. CDC advice the public and particularly those at higher risk of influenza-related infection, to take every day preventive actions like covering mouth and nose while coughing and sneezing and staying home from school or work if they’re ill to reduce spreading of illness.
Then WHO raised the influenza virus alert to phase 5 on April 29, 2009, and recommended all countries to immediately start their virus awareness plans and watch out for unusual occurance of influenza-like illness and severe pneumonia. By then CDC continued to post and update regulation for clinicians, laboratories, schools, partners and the public on topics such as non-pharmaceutical actions that limits the spread of illness, how to assess a patient for possible infection with 2009 H1N1 influenza and how to treat children who is infected with 2009 H1N1 influenza.
CDC also released an MMWR Dispatch on the outbreak of 2009 H1N1 influenza illness in a New York City high school, on April 30, 2009, which was the largest cluster of 2009 H1N1 cases in the United States at that time. The Dispatch stated that the high school students had fever and respiratory symptoms similar to the seasonal flu, additionally around half the students had diarrhea.
As the illness spread, CDC began receiving reports of school closures where school administrators and public health officials followed the prescribed virus prevention plans. And the public even implement community-level social distancing such as increasing distance between people, staying at home when ill unless for medical needs, avoiding large gatherings, by telecommuting. And then CDC’s Travel Health Warning advising people to avoid non-essential travel to Mexico which was in effect since April 27, 2009, was downgraded to a Travel Health Precaution on May 15, 2009.
