The death toll due to swine flu around the world has swelled to around 800, World Health Organisation has reported.
The A(H1N1) virus that first caused illness in Mexico and the US in March and April is continuing to spread through the world, the UN body said yesterday.
WHO spokesperson Gregory Hartl warned that the virus is expected to increase this winter in the Northern Hemisphere due to cold weather.
Dr Anne Schuchat, director of the Center for Disease Control and Prevention's (CDC) National Center for Immunisation and Respiratory Diseases, agreed to this saying "We had a 6 to 8 per cent attack rate just during the spring months... We think that in a longer winter season, attack rates would be two to three times as high as that."
Around 160 countries and territories have now reported laboratory-confirmed cases of the virus, but how it could potentially change over the coming weeks is still unknown, the WHO spokesperson told reporters in Geneva.
Meanwhile, the US officials say that the swine flu could end up affecting as many as 40 per cent of Americans, if one includes workers who stay home to care for people who contract the illness.
"Our assumptions for a severe pandemic were that up to 40 per cent of the workforce might be affected and not able to work either because they were ill or they needed to stay home to care for an ill family member," they said.
The CDC reported that there have been 43,771 confirmed cases of H1N1 virus and 302 deaths in the US, but officials believe that over one million Americans have been stricken with swine flu.
The highest percentages of deaths from the pandemic are among adolescents and youths, he said, adding that the virus is likely to spread more quickly in schools and institutions. WHO expects the first doses of vaccine against A(H1N1) to be ready by early fall.
Two manufacturers have guaranteed that 150 million doses will be made available and the agency is pressing other partners to secure more doses, Hartl pointed out.
The projection from the CDC is based on influenza pandemic in 1957 when almost 70,000 people in the US died from the flu.
A public health campaign and a vaccination programme, which will probably begin in October, can reduce the impact of the swine flu, she said.
Vaccine trials, already underway in Australia, are expected to begin in the US next week, Schuchat said. US officials hope to have 160 million doses of injectable swine flu vaccine on hand by October, with more doses coming in the form of a nasal spray -- if trials of experimental vaccines are successful.
