Staying alert to the influenza threat

opinion April 19, 2013 00:00

By The Straits Times
Asia News N

Compared with the H5N1 and H1N1 outbreaks, there are few signs of panic over the newest H7N9 influenza strain that originated in China last month. Slow spread could be one reason, but confidence has also grown with the country's better management of publ

There is now an openness about reporting H7N9 cases and sharing of viral genetic data with the World Health Organisation’s (WHO) network of flu laboratories. Such steps will accelerate the search for a vaccine and help produce a diagnostic test to confirm infections quickly, if they become widespread across borders. Having the world’s most populous nation firmly in the epidemiological notification loop is an important advance in transnational disease control.

Beijing has rightly drawn approval for the change, a far cry from its old habit of keeping even its own people in the dark about pestilence. But these are early days, so vigilance is warranted. There is no telling how the virus might mutate or whether it will migrate from poultry to pigs, which a virologist of America’s Centres for Disease Control and Prevention says would be “bad news”, as it could create new strains. The deadly H1N1 virus was a result of swapped genes drawn from three species.
Singapore as a crossroads node is, as usual, vulnerable. Early notice of probable control measures at Changi Airport is by no means hasty, as indeterminate Sars-like infections have been reported in West Asia besides the H7N9 cases.
There are plenty of clinical mysteries about the H7N9 outbreak that counsel caution, as with previous respiratory epidemics. One poser is the high death rate (20 per cent) relative to the low number of infections so far (about 60). The Sars contagion in 2003 had 10 per cent deaths from some 8,000 cases worldwide. Does it suggest H7N9 is of the acute variety, or would morbidity decrease if the infection pool gets bigger? 
Another poser is the likelihood of transmission between humans, beyond the current poultry-to-human chain. The WHO is cautious in saying that there is no evidence of that happening yet, only that this virus appears to infect mammals, like humans, more readily.
The fact that the original cluster has spread to northern and central China has put health authorities on heightened alert. Governments cannot take chances while waiting for a vaccine, which could take a year or longer to create. A pandemic could have taken hold by then. Just as theoretically possible is that H7N9 could turn out to be short-lived. 
Why risk it? Border surveillance as a pre-emptive response should be considered, with or without an advisory from the WHO.