It’s been more than six months since the swine flu epidemic erupted worldwide and in that time we have seen at least two major waves of illness around the northern hemisphere. The first was in our summer as the new virus spread in pockets after international travellers returned home already infected and affected wider populations in specific areas, particularly noticable when attributed to schools. The second wave started when the schools went back in September, in advance of our real winter which is only just beginning now, but peaked within weeks as the warm autumn weather held the virus in check.

November is traditionally the start of the flu season and this year is no exception apart from the fact that the flu virus in circulation is in most cases much more likely to be the new variant of type A H1N1 rather than the usual human h5n1 seasonal flu virus.

So this is either a third wave or a reprise of the second wave if you prefer, and the signs are that this has just passed a temporary peak, with the number of new reported cases dropping week on week for the first time (UK estimate 46,000 new cases of swine flu in the last week, down from 53,000 week before.) An important question now is whether or not there are any signs of the virus mutating into a type that is more deadly as has happened previously in history with influenza pandemics caused by new strains. The pattern to look out for is one of successive waves of increasing numbers infected, followed eventually by one or more waves which are not only more deadly to victims but also more easily transmittable. Then eventually once a tragic number of fatalities have been cleared away, the flu virus mutates into a milder form that goes on to infect the rest of the world’s population who haven’t already acquired immunity, but without taking nearly such a bad toll in terms of lives. It is reasoned that it’s for this eventuality that various governments have planned vaccination programmes for whole populations, at present being implemented first only for the most “at risk” demographics -  young people, children and those with underlying health problems.

For the UK, another important fear is if the virus becomes resistant to the antiviral drug Tamiflu, since the government has taken the precaution of buying in huge stocks of the tablets, enough to treat one half of the country’s population.

The Thanksgiving holiday is typically followed by at least a modest bump in early seasonal flu cases, according to reports from the past few years. But this, of course, is not a typical year. Swine flu is a new virus that accounts for nearly all flu cases right now. Usually, seasonal flu is just getting going in late November, and holiday get-togethers allow illness to jump from small pockets to other parts of the country. Swine flu, in contrast, has been widespread for months.

“It’s not like we expect to see a bunch of infected people going to uninfected cities and towns”

said Andrew Pekosz, a flu expert at Johns Hopkins University. The swine flu pandemic hit the US in two waves: first in the spring, then a larger wave that started in the late summer.

The World Health Organization said H1N1 flu was moving eastward across Europe and Asia after appearing to peak in parts of Western Europe and the United States.

Mutations of the DNA of influenza viruses are typical of any pandemic and world experts are watching carefully for any first signs of a dangerous mutation. So far the indications are that early warning systems are working but that no such mutation with a deadly combination of easy transmission, deadly payload and/or drugs resistance has shown up – yet. Isolated cases of different mutations have been reported from Brazil, Norway and China and drug resistance in a hospital in Wales.

from MetroNews.CA Toronto

WHO’s spokeswoman in Beijing, Vivian Tan, said the agency is aware of three such cases in China that occurred in June and July that were similar to the cases being investigated in Norway. Tan said WHO had no information on the cases mentioned in the Xinhua report Wednesday.

There is no evidence the mutated swine flu virus is circulating widely in the world, Tan said, but since it has been linked to deaths in Norway and elsewhere, investigators are focusing on whether this mutation could be a marker for more severe disease.

“We are concerned, but realize that influenza viruses, including A/H1N1, are relatively unstable and change easily, especially as they infect more people,” Tan told The Associated Press. “Some mutations can have minimal effects on how a virus functions, while other mutations can create important changes with significant public health impact.”

Several troubling outbreaks of drug-resistant H1N1 have been documented but it has been noted they are limited so far and there are no indications yet that the virus is mutating in a sustained way.

Saudi authorities announced four pilgrims have died of the H1N1 swine flu virus in the days leading up to the pilgrimage which began on Wednesday 26th November 2009. A Moroccan woman, a Sudanese man and an Indian man, all 75, and a 17-year-old Nigerian girl, died from H1N. The Saudi Health Ministry said the four had not followed ”recommended procedures, especially vaccination against swine flu”.

All the victims so far had been suffering from underlying health conditions with 16 other cases of swine flu infection among pilgrims. Health authorities in Saudi have mobilised for the world’s largest gathering since swine flu began spreading across the globe, but the number of pilgrims going on Hajj is likely to be lower this year due to rainstorms, and local officials admitting that fears of swine flu may keep away at least 40 percent of local pilgrims.

A Tamiflu resistant strain of the swine flu has spread between hospital patients in Cardiff, Wales.  They are thought to be the first confirmed cases of person-to-person transmission of a Tamiflu resistant strain in the world. Five patients at Cardiff’s University Hospital of Wales appear to have acquired the infection while being treated for other conditions, and these have now been joined by a sixth related case of the drug resistent flu strain.

The H1N1 virus has been remarkably stable since it emerged in April, but virologists had been half expecting new resistant strains to emerge somewhere in the world, and it appears to have happened first at the University Hospital of Wales in  Cardiff.

Scientists in Norway announced recently that they had detected a mutated form of the swine flu virus in two patients who died of the flu and a third who was severely ill. The Norwegian mutation could possibly make the virus more prone to infect deeper in the airways and thus cause more severe disease, such as pneumonia. Influenza is a mutable virus, and changes are to be expected, this is typical early in the spread of a pandemic virus.

Some 680,000 Norwegians are estimated to have been infected with swine flu to date, of which 23 have died.

WHO says there have been over 6,750 deaths worldwide so far.

Although the world was alerted to the new strain of flu virus spreading in Mexico City back in April, the preparations made for a vaccination programme have been effected later than was originally hoped. Last  week in the UK for example, it was announced that more than three million healthy children under five across the UK will be offered the swine flu jab, whereas the announcements back before the summer were that a widespread vaccination programme would begin in September. Over in France, the first cases of a vaccine induced illness have been reported, reviving fears of a repeat of the terrible situation in the US during the 1975 pandemic when a vaccination programme was halted due to large numbers of tragic side effects.