MEXICO CITY: Mexico confirmed two more deaths from the H1N1 flu virus yesterday, pushing the country’s toll to 44 as the virus spread slowly in Europe. The World Health Organization (WHO) said that up to two billion people could be infected by swine flu if the current outbreak turns into a pandemic. But China eased quarantine measures and Mexico said the worst is over and millions of high school and university students returned to classes.

Global health officials, who hope their warnings have helped brake the disease’s spread, debated whether the swine flu was spreading enough to justify calling it a pandemic.

WHO flu chief Keiji Fukuda said the number two billion was not a prediction, but that experience with flu pandemics showed one-third of the world’s population gets infected and they typically last two years.

The Netherlands confirmed a second case of the virus, in a 53-year-old woman who had been to Mexico. The United States has 896 confirmed cases of the flu in 41 states, the Centers for Disease Control and Prevention said.

After a five-day business shutdown, the Mexican government has let cinemas, restaurants and workplaces reopen. But visitors to government-run buildings were asked to wear surgical masks and wash their hands with anti-bacterial soap before entering. Restaurants also sanitized diners’ hands as they arrived.

H1N1, which has killed a woman and a child in the United States but no one else outside Mexico, has reached 24 countries and infected more than 2,000 people, according to data from the WHO and national authorities.

Sweden and Poland confirmed their first cases on Wednesday.

China began lifting a seven-day quarantine for passengers who had arrived on a flight from Mexico City that included a man who tested positive for H1N1, the Health Ministry said.

The WHO now finds itself in a bind about how to respond to the spread of the virus whose effects have proved mainly mild. The UN agency’s guidelines state that as soon as the virus starts spreading freely in two regions of the world, its six-point pandemic alert should be raised to the top notch.

With infection numbers rising in Europe, public health experts are struggling to decide whether it is worth sounding the full alarm over H1N1, which is treatable with existing drugs and appears less severe than seasonal flu in most cases.

People react differently to the flu depending on their general state of health and other factors. Some younger people in the Southern Hemisphere may be more vulnerable because of malnourishment, war, HIV infections and other factors, Fukuda said.