Blossoms continue to monitor the 'swine flu' situation.

As of 06:00 GMT, 10 June 2009, 74 countries have officially reported 27,737 cases of influenza A(H1N1) infection, including 141 deaths, which equates to 0.5% mortality rate, significantly below seasonal flu mortality rates.

It is widely anticipated that the World Health Organisation (WHO) will officially declare a pandemic imminently.  The move to pandemic Phase 6 is official confirmation that the virus will continue to spread globally.  It is not a signal that the virus is getting more virulent or severe, rather, it is a measure of geographical spread.

Several manufacturers now have an H1N1 seed virus strain, and will be completing safety and efficacy testing in the coming months.  It is not clear how well the virus will grow or how many doses people will need to be protected.  The first bulk doses might be ready in the late autumn and would most likely be earmarked for frontline emergency staff and those with chronic respiratory problems.

Several dozen researchers, led by Rebecca Garten of the CDC, recently sequenced full or partial genomes of 76 samples of the new virus.  In a paper published in Science, they confirm that the closest genetic relatives of the new virus are swine-flu strains from both North America and Eurasia. 

The virus has been shown to be made of eight gene segments of known provenance, but which have not previously been seen in this combination.  The genetic material in them is a hotchpotch derived from avian, human and swine sources, but all eight segments come most recently from pigs.

The researchers have discovered that the antigens (proteins that provoke an immune response) found in different samples have remained similar to each other.  That, according to Derek Smith of Cambridge University, one of the paper's authors, may make it easier to design a vaccine against the new virus, although it is still possible that by the time an H1N1 vaccine is ready, the virus will already be spreading rapidly in the Northern Hemisphere.

Canadian officals also recently confirmed that the new strain has hopped from humans back into pigs in Alberta.  Because swine are natural mixing vessels for influenza strains from different species (hence the hotchpotch found by Dr Garten and her colleagues), a concern exists that the virus could mutate again and jump back into humans.

Although the vast majority of people who get H1N1 swine flu have a mild illness, a study by the Centres for Disease Control (CDC) has found that nearly two-thirds of swine-flu infections in America have been in people aged between five and 24, whereas only 1% of cases affected those over 65.  The WHO estimates that about half the 141 deaths so far have been in young people who were previously healthy.  Both studies show a reverse of the pattern normally seen in seasonal flu.

One possible explanation, according to Anne Schuchat of the CDC, is that "older adults might have been in contact a long time ago with a virus similar to the one we see now".  That, she surmises, might give them an immunity to the new virus that young people lack.

WHO health advice remains not to restrict international travel.  It is considered prudent for people who are ill to delay international travel and for people developing symptoms following travel to seek medical attention.

Blossoms advice is to focus on clearly educating employees about good personal hygiene, what to do if symptoms present and to plan for a likely increase in absence levels during the traditional flu season (late September onwards), perhaps by planning to facilitate remote working if possible.

Blossoms will continue to monitor the situation and advise clients accordingly, although please don't hesitate to contact us at any time if there is any further support or guidance we can provide.