Will H1N1 be back in deadly second wave?

By Ng Wan Ching

THE first wave of swine origin Influenza A (H1N1) appears to be tapering off, but it is too early to relax.

Some experts, including Dr Margaret Chan, the World Health Organisation's (WHO) director-general, are warning of the possibility of a more deadly second wave.

But viruses are notoriously unpredictable. There is also a chance that the virus might disappear from the northern hemisphere with the summer sunshine of June, July, August.

One hypothesis is that the extra UV light during the summer months kills off viruses.

Although let's not forget the southern hemisphere, which will experience winter between June and September, and that potential pandemic viruses are not always afraid of warm weather.

Right now, people from 30 countries are suffering a relatively mild outbreak.

For the virus to come back in a more lethal second wave, it would have to follow the same path as the 1918 virus which killed an estimated 50million people worldwide.

It would have to spread readily enough in humans so that it does not fizzle out, and it needs to mutate to a nastier form capable of killing more people.

World War I did not cause the flu, but the close troop quarters and massive troop movements hastened the pandemic. Some researchers speculate that the soldiers' immune systems were weakened by malnourishment, and the stresses of combat and chemical attacks, increasing their susceptibility to the disease.

Most devastating

The flu pandemic of 1918 has been called the most devastating epidemic in recorded world history. Outbreaks swept through North America, Europe, Asia, Africa, Brazil and the South Pacific.

It seems unlikely that H1N1 will simply fizzle out. Some experts think it might become the dominant strain of circulating seasonal flu.

There is no indication right now that there will be a 'second wave' for Singapore. In fact, there may not even have been a first wave outside of North America.

According to Associate Professor Paul Ananth Tambyah, Head of the National University Hospital's Division of Infectious Diseases, chances are 60/40 that the swine origin H1N1 is going to become the main circulating strain of seasonal flu.

'And this might just become a rather nasty flu season like the one we had in 2003/04 with the Fujian Flu,' he said.

The Fujian flu virus caused an unusually severe 2003 to 2004 flu season.

Countries in the north such as the US and those in Europe faced one of the worst flu seasons in December 2003. France reported up to two million cases, while in Spain, it affected 195 people in every 100,000 - a toll 20 times higher than in previous years.

In the UK, seven children died. In Colorado in the US, at least five children died in December 2003, compared with only one or two each year.

Still, it was nothing like the 1918 flu.

Of the three flu pandemics the world has seen, Singapore suffered a lethal second wave only in the 1918 pandemic.

The second waves in the 1957 and 1968 pandemics were milder than the first waves for Singapore and the rest of the world.

'But then again, the world was at war (in 1918) so it is not clear whether it was virological or sociological why the mortality was higher the second time round,' said Assoc Prof Tambyah.

Doctors noted that in the 1918 pandemic, those who got the virus in the first wave and survived it, were immune to the more virulent virus in the second wave.

But it would not be a good strategy to allow people to get infected with H1N1, because they might get infected with seasonal flu at the same time and the two viruses might mix and share genes, said Assoc Prof Tambyah.

The seasonal flu is resistant to oseltamivir (Tamiflu) while H1N1 is not. If H1N1 becomes the major seasonal flu, it will be harder to treat as doctors might have to use combinations of other anti-viral agents.

Anti-flu ammunition

The world is now armed with more ammunition to fight the flu virus.

One difference between 1918 and now is the possibility of a vaccine.

If this mild outbreak of H1N1 is followed by a more lethal wave later in the year, pharmaceutical companies could make vaccines against what is circulating now and hope they will work against whatever the virus turns into.

Production of ordinary flu vaccine for the next northern winter is well under way, and the plan, said WHO, is to finish this run and then turn the factories over to producing the H1N1 vaccine, which could happen as early as June.

There are fears of a similar outcome to the 1976 H1N1 swine flu vaccination programme, which ended after a few hundred people developed a severe paralysing nerve disease. But seasonal flu vaccines since then have all included H1N1 strains without any problems.

What is important now is to ensure that governments the world over, including Singapore, have enough of a stockpile of anti-viral drugs to treat its citizens.

The WHO recommends stockpiles for 20 to 25 per cent of the population.

Health Minister Khaw Boon Wan has stated that Singapore has stockpiled 1.15 million courses of Tamiflu and 50,000 courses of Relenza (another anti-viral) which meets WHO recommendations.

At the moment, Tamiflu seems effective against H1N1.

'I am sure that many of the anti-influenza drugs that are in the pipeline, in addition to those already on the market, will be hastened to market in order to prepare for the possibility that H1N1 becomes oseltamivir (Tamiflu) resistant,' said Assoc Prof Tambyah.

Access to treatment

Many of those who died in earlier pandemics, especially the Spanish one, did not get access to treatment early enough.

It is estimated that one in three of the cases died from the Spanish flu virus but two in three died from complications of the virus including secondary infections.

Every year, there are small mutations in the flu virus and older people or those with other medical conditions get sick and some die from influenza.

'We have good ICU facilities and excellent cardiac and respiratory specialists so the complications of influenza if and when they occur can be well treated,' said Assoc Prof Tambyah.

Crowd control

Some studies have shown that social distancing measures are still best - such as isolating patients and their contacts.

That was what Mexico did for five days during the height of the H1N1 outbreak. And it seems to have worked.

The studies in the US showed that cities that applied these measures, early and long enough, cut the number of deaths.

As Mr Khaw said two weeks ago, every month that Singapore can delay the flu attack means time bought to enhance protection for those who live here.

'Manufacturers are rushing to produce vaccines but they need several months to a year. For every month we can delay the flu attack, we enhance our chances of protecting Singaporeans,' he said.

In the overall scheme of things, it pays to be over-prepared.

There are new viruses brewing all the time in the animal world.

That includes H5N1 (bird flu) which has been simmering in Asia and Africa. It could achieve efficient human to human transmission any time and trigger a pandemic.

Now is the time to stockpile not just enough anti-virals for Singaporeans but also enough personal protection equipment for all healthcare workers.

And hopefully Assoc Prof Tambyah will be proven right.

'I am cautiously optimistic that even if there is going to be a strong first wave or second wave, we will be prepared,' he said.

This article was first published in The New Paper.