The Centers for Disease Control and Prevention said Friday that the number of U.S. cases rose to 141 in 19 states, up from the previous tally of 109 logged Thursday.
In Hong Kong, the first case of the H1N1 flu in Asia was confirmed in a Mexican traveler, which prompted authorities to seal off the hotel where the patient was staying, according to Reuters. The Mexican reportedly was in a hospital in stable condition.
Denmark also confirmed its first case of H1N1 flu in a person infected in New York City, the head of Denmark's Board of Health, Jesper Fisker, said Friday. He said the person was nearly recovered but would remain in isolation until May 6, Reuters reported.
In Mexico City, where many offices and businesses were closed for a five-day break to help slow the spread of the disease, Mayor Marcelo Ebrard said the country's emergency campaign against the virus was bringing results.
"Individuals and families have been taking these measures very seriously and as a result we have had timely and early detection of cases of respiratory illnesses that could be of this type. This has led us to a situation where the numbers are getting better every day," he said, quoted Reuters.
"I'm not saying we should let our guard down ... I'm telling you so you know where we stand."
Mexican Health Minister Jose Angel Cordova said the public hospitals that treat roughly half the country admitted just 46 patients with severe flu symptoms Thursday, down from 212 patients on April 20.
The CDC said in a report issued Friday it had confirmed 84 out of up to 176 deaths in Mexico were from the H1N1 strain.
Meanwhile, the World Health Organization said Friday that tests show the current seasonal vaccine against flu would have little effect against the new H1N1 strain.
"There is very little chance that the seasonal vaccine ... will be effective against this particular virus," Marie-Paule Kieny, director of the WHO's initiative for vaccine research, told a news conference, Reuters reported.
She went on to say she had no doubt making a successful vaccine is possible and would take between four and six months for the first doses to be available. Samples needed to make a vaccine would be ready to send to manufacturers by mid to late May, she added.