The study that could take the doubt from Mers

A serological study can answer many questions over Mers-CoV.

The death of a Jordanian woman in Abu Dhabi from the Middle East Respiratory Syndrome coronavirus (Mers-CoV) is a deeply personal tragedy for the family involved, made worse by the fact that the woman was in the last stage of pregnancy. One small blessing is that the baby girl she was carrying was delivered safely and is not infected, and that her husband and son – who did become ill – are now said to be in a stable condition.

The woman’s death is the 70th from this relatively new disease, a variant of the Sars virus that swept the Far East a decade ago. Since the first cases were reported in September last year, research by the World Health Organisation and many other bodies has been intensive. Much is now understood about Mers.

It is believed to originate in bats – as did Sars – but can also be transmitted to camels. How it passes from bats to camels, and from both to humans, remains unknown however.

In some circumstances it is known to be highly contagious and a cluster of infections can be traced back to a single source. But these examples are rare. Most people who fall ill from Mers are not known to have had contact with other victims: and more significantly, most are elderly or have pre-existing conditions – or both.

This has led some experts to wonder if Mers may be more widespread than the official figures would suggest (just 163 cases worldwide in 15 months). It could be, the experts suggest, that the vast majority of people who contract the virus are barely aware that they are infected. If this is indeed the case, then fears that Mers could spark a wider epidemic similar to Sars in 2002-2003 would be unfounded.

There is one relatively easy way to test this thesis: through a serological study using blood samples taken in hospitals for other purposes, to see the level of antibodies they contain. If samples show that many people have come into contact with Mers-CoV but have not experienced significant illness, then the risk of an epidemic is low.

However, if the samples show few have been infected but those who have done so have become gravely ill, then the potential for an epidemic would be much higher.

As Saudi Arabia seems to be the major seat of the illness, we would urge the Saudi authorities to institute a serological survey without delay.