Two men who were infected with the H1N1 swine flu virus died during the past two days, making them the 17th and 18th Israeli victims of this strain of influenza, even though it was not certain that their deaths were due to the virus. One was a 62-year-old man suffering from a serious chronic condition who died at Sourasky Medical Center in Tel Aviv. The other was a 49-year-old man who was obese and had a chronic lung problem and died Sunday at Kaplan Medical Center in Rehovot. The World Health Organization in Geneva has advised countries in the Northern Hemisphere to prepare for a second wave of flu pandemic. The H1N1 pandemic virus is the dominant influenza strain now in most parts of the world, even though it is seasonal flu season in the Southern Hemisphere. Seasonal flu in Japan is becoming more common now than H1N1 flu there, the WHO said. In the Southern Hemisphere, most countries - such as Chile, Argentina, New Zealand and Australia - appear to have passed their peak of influenza activity, WHO officials said Friday. However, South Africa and Bolivia continue to experience high levels of influenza. Many countries in tropical regions in Central America and Asia continue to see increasing or sustained high levels of H1N1 influenza activity. Some of them are reporting moderate strains on their healthcare systems. In North America, Europe and Central Asia, influenza and respiratory disease activity remains low overall, with some countries experiencing localized outbreaks. However, H1N1 flu activity appears to be increasing in the southeastern US, where some cities report nearly 15 percent of hospitalized patients with the flu have required intensive care. The Health Ministry, led by Deputy Minister Ya'acov Litzman and Education Minister Gideon Sa'ar, held a meeting on Sunday assessing plans for coping with the H1N1 flu threat to the educational system. It was decided that there was no need to delay the opening of schools and other academic institutions, but that pupils, teachers, principals and parents who have symptoms of the flu and are not in high-risk groups should not enter schools until they have recovered. Children and teens who are not at high risk almost always have mild cases of the flu (whether H1N1 or seasonal) and recover without complications. They need not go to the doctor unless they have unusual or serious symptoms. The ministers agreed that while children who stay away from school due to illness have to bring a doctorâ€šs note saying they have recovered, they will not be required to bring such a note after recovering from the flu, as it is better for them to stay home and not go to the clinic and spread their infection. Twenty-four hours after their fever disappears, they will be allowed to return to school, the ministries said, however they must bring a parentâ€šs note confirming that the child has recovered.