Swine Flu Update: 21/08/2009

In certain ways, the past few weeks of the Swine Flu outbreak have been positive for everyone involved. Numbers of cases have decreased steadily and as a result, GP consultation rates have diminished too. In addition, the majority of patients continue to suffer only mild reactions and there are no signs of any impending mutations - either in terms of the severity of the virus itself, or with regards to anti-viral resistance. News on the development and testing of the new H1N1 vaccine continues to impress and estimates continue to predict the emergence of the first batch of drugs around October – with the hope that at least 50% of government stocks may be delivered by the New Year. Whilst some questions have been raised over the reliability of HPA figures since the move to the National Pandemic Flu Service (NPFS), there were an estimated 11,000 new cases reported for last week, compared to a considerably higher 25,000 new cases for the week before. Reflecting the drop in the number of actual cases of H1N1, GP consultation rates also declined steadily, falling from an initial 30.9 per 100,000 to 21.1 per 100,000 for the week just passed. The week also witnessed a further 10 swine-flu related deaths, bringing the total number of UK fatalities to 54.
Yet for all the positive news of the past week or so, there is absolutely no cause for complacency. To a certain degree, the most recent fall – however substantial – was somewhat to be expected, with officials fully aware that initial fluctuations were possible – leading up to an eventual zenith over the duration of the winter months. Indeed, in echoing the words of the UK’s Chief Medical Officer Sir Liam Donaldson, even more recent comments from the WHO’s Western Pacific director, Shin Young-soo, suggest that winter trouble is most definitely ahead. "At a certain point, there will seem to be an explosion in case numbers”, he said, adding that "It is certain there will be more cases and more deaths”. Almost unquestionably, the worst is not yet over.

"As of this week, there have been more than 182,000 laboratory confirmed cases of pandemic influenza H1N1, 1799 deaths, in 177 countries and territories have been reported to WHO. As more and more countries have stopped counting individual cases, particularly of milder illness, the case number is significantly lower than the actually number of cases that have occurred. However, through the WHO monitoring network, it is apparent that rates of influenza illness continue to decline in the temperate regions of the southern hemisphere, except in South Africa where pandemic influenza H1N1 appeared slightly later than the other countries of the region. Active transmission is still seen in some later affected areas of Australia, Chile and Argentina even as national rates decrease.
Areas of tropical Asia are reporting increasing rates of illness as they enter their monsoon season, as represented by India, Thailand, Malaysia, and Hong Kong, four places in the region which have active surveillance programs. Tropical regions of Central America, represented by Costa Rica and El Salvador, are also seeing very active transmission.
In the northern temperate zones, overall rates are declining in both North America and Europe though the virus is still found across a wide area throughout both regions and pockets of high activity are being reported in 3 U.S. states and a few countries of Western Europe.
It has been noted throughout the temperate zones of the southern hemisphere, which are now passing out of their winter season, that when pandemic H1N1 began to circulate, the relative importance of seasonal strains, represented by H3N2 in nearly all countries, rapidly diminished and pandemic H1N1 became the dominant strain. Some seasonal H1N1 strains were reported but were even less common than seasonal H3N2. It is too early to tell if this co-circulation of multiple strains will continue into the coming season of the Northern Hemisphere but it appears very likely that pandemic H1N1 will be the dominant influenza virus in the early part of the winter months.
Many countries including Australia, Canada, New Zealand, and the U.S. have noted that their indigenous peoples appear to be at increased risk of severe disease related to pandemic influenza. While it still has not been clearly determined how much of the increased risk observed in these groups is due to issues related to access to care, high rates of chronic medical conditions that are known to increase risk, or other factors, countries with indigenous and other vulnerable populations should carefully evaluate the situation and consider ways to mitigate the impact of the pandemic in the coming season in these populations.
WHO has also been notified of 12 cases of oseltamivir resistant virus. These isolates have a mutation in the neuraminidase (referred to as H275Y) that confers resistance to oseltamivir, though the viruses remain sensitive to zanamivir. Of these 8 have been associated with oseltamivir post exposure prophylaxis, one with treatment of uncomplicated illness, and two have been from immunocompromised patients receiving oseltamivir treatment. These isolated cases have arisen in different parts of the world (Japan 4, USA 2, China, Hong Kong SAR China 2, and 1 in Denmark, Canada, Singapore and China), and there are no epidemiological links between them. There is also no evidence of onward transmission from these cases".
*The information above is a copy of the latest WHO regulations and guidelines for Swine Flu and can be found in more detail at the WHO Website, here.
• There has been a further reduction in the rates of flu-like illness and related activity this week. There were an estimated 11,000 new cases this week compared to 25,000 new cases last week. • Weekly GP consultation rates decreased over the last week in England. • There are 263 patients in hospital with swine flu, 30 of whom are in critical care. • There have been 54 confirmed deaths in England. • There is still no sign of the virus mutating into a more dangerous form, or developing resistance to drugs*
*The information above is a copy of the latest NHS key updates for Swine Flu and can be found in more detail at the NHS Swine Flu Website, here.
• WHO Twitter – ‘WHO's official Twitter channel. Who is the directing and coordinating authority within the UN system for public health’. • NHS Swine Flu Overview – ‘This page brings together the latest science and developments on the swine flu pandemic into a single accessible resource for both health professionals and the general public’. • NHS Swine Flu Vaccine – Detailed information on the development of the H1N1 vaccine, along with logistical updates on clinical trials in the U.S. and Australia, efficacy and WHO recommendations. • The Lancet H1N1 Flu Resource Centre – With over 40 journals, Lancet is one of the leading scholarly resources on the topic of Swine Flu – if not any healthcare issue. With free, unlimited access for all, this is one powerful research resource. • Nature – A number of interesting feature articles and blogs pertaining to the topic of Swine Flu. • Fergus on flu – Great Swine Flu blog from the BBC’s Chief Medical Correspondent. • Microsoft Bing Swine Flu Tracker – ‘Map of 2009 Swine Flu H1N1 outbreaks and migration paths reported from news and government agencies. The map lists reported dates and paths of infected persons traveling’. • Facebook Group for H1N1 – With over 3,500 members – and literally hundreds of personal accounts on the current outbreak, this Facebook Group provides an interesting view into the potential future impact of Social Media on healthcare related issues.