To sound Mers alarm or not...

WASHINGTON - Despite the growing number of Mers-related deaths, the World Health Organisation (WHO) has not declared it a public health emergency or issued a travel advisory against Saudi Arabia, where the virus is thought to have originated, prompting questions about the inaction.

When Sars broke out in 2003, travel advisories were issued in March when there were 167 cases and four deaths. Already, the toll for Mers - Middle East respiratory syndrome - has surpassed that; as of May 16, there were 614 cases and 181 deaths.

Some experts believe Mers should be declared a public health emergency. Dr Preben Aavitsland, former state epidemiologist for Norway, believes that doing so could "stimulate even more international sharing of information and international assistance and coordination in the study of this new disease".

He says this would help the international community find out more about the source and transmission of the virus. If WHO were to issue travel advisories, Dr Aavitsland acknowledges, it would interfere with trade and tourism. But he feels it would also lower the number of exported cases.

But if one were to look at epidemiological evidence alone, that might suggest why the WHO has not pushed the panic button as yet. When Sars broke out, "it was just so scary", says Associate Professor Rachel Roper, who specialises in virology at East Carolina University. "This is just not at that level."

The key difference is transmissibility, with Mers appearing to be less infectious than Sars.

Health experts say Sars could clearly be exported to other countries and was spread locally in those communities. Even though Mers has spread to other countries - 18, according to the Centres for Disease Control and Prevention in the United States - there is no "sustained transmission" in these places.

Sustained transmission is the transfer of the disease from the original source to a second, third and fourth person, "a bit more like how influenza is transmitted", says Professor William Schaffner, infectious disease and public health specialist at Vanderbilt University School of Medicine. "If you have that kind of casual community transmission, not just in families, not just in the health-care setting, then it becomes a much larger hazard and I think that's when the WHO would put travel advisories in place."

But isn't the Mers fatality rate of 30 per cent - much higher than that of Sars which was about 9 per cent - enough to sound alarm bells?

While "Mers appears more deadly than Sars, at the moment", Prof Schaffner says, fatality rates are likely to change as investigations are ongoing. He says the current statistics capture only severe cases and not those who think they have the common cold.

From a legal perspective, law professor David Fidler says WHO has "political and economic concerns" when it declares travel advisories because it "carries a lot of weight". He adds that neither China nor Canada was happy when the advisories against travel there were issued during Sars.

But Prof Fidler, who is also a fellow at the Chatham House Centre on Global Health Security, does not buy the argument that WHO has "no political stomach" to declare a public health emergency and issue temporary recommendations, given that it just did so for polio.

He adds that WHO has a legal mandate to focus on the epidemiology for its decision and with each meeting "while they say not yet, they are saying we're closer this time".

simlinoi@sph.com.sg

This article was first published on May 25, 2014.
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