Global Health Press
One year later, MERS virus remains largely a mystery

One year later, MERS virus remains largely a mystery

A year after SARS hit the world’s radar, scads had been learned about the virus that set off outbreaks in China, Hong Kong, Toronto and other spots, and ignited panic far beyond the affected centres.

The coronavirus was rapidly discovered, it genome sequenced within weeks of the World Health Organization warning on March 15, 2003, of its existence and spread. The animals that transmitted it to people had been identified. Doctors knew when SARS patients were infectious and what steps needed to be taken to stop its spread. With that knowledge, the virus was quickly contained. SARS is medical history.

Later this week — Friday — will mark a year since the world learned that a cousin of the SARS virus had burst out of some hiding spot in nature to infect and kill a man in Saudi Arabia. Since then, the world has learned of roughly 130 MERS cases, 57 of them fatal.

But in contrast to the SARS outbreak, at this point relatively little is known about MERS. With several million Muslim pilgrims descending on Saudi Arabia — the hottest of MERS hot spots — in coming weeks for the annual Hajj, there is a real sense of worry among scientists watching the outbreak.

Many scientists are at a loss to diplomatically explain the lack of progress.

“We knew more in two to three weeks with SARS than we probably even know now. Maybe it’s three to four weeks,” says Dr. Larry Anderson, the scientist who led the U.S. Centers for Disease Control’s SARS response a decade ago.

Anderson, who now teaches in the medical school at Emory University in Atlanta, says he finds the state of the scientific world’s MERS knowledge “concerning and sad.”

“I think some opportunities clearly have been missed, and it’s surprising to me that we don’t know more than we do,” he says.

“It has put the world at some risk — I don’t know if it’s a large risk or small risk — that we’re not as prepared as we could be if we had some of this information. And if it (the virus) … took off, it would look really bad, I think.”

The director of the Center for Infectious Diseases Research and Policy at the University of Minnesota says he cannot understand why global health bodies like the World Health Organization and governments like his own aren’t publicly complaining about the lack of information.

“This is not just a curiosity exercise. This is a global obligation that the public health officials in the Middle East have in terms of preparing the world for a potential global event,” Michael Osterholm says.

“We all as a global public health community have a right to know what’s being done to stop these ongoing transmissions because this could be in our lap tomorrow.”

A year after the WHO’s first SARS alert, more than 1,000 journal papers had been written about severe acute respiratory syndrome. At this point, a search for MERS in the PubMed, an online index of scientific papers maintained by the U.S. National Library of Medicine, draws up about 200 hits. Important papers, the ones that flesh out detail of this new disease, are a portion of that total.

Last week, one of the biggest annual infectious diseases conferences in the world took place in Denver, Colo. There wasn’t a single presentation on MERS made at the meeting.

“I think that is a reflection of what studies are actually being done, particularly in the U.S.,” says Dr. Mark Pallansch, who heads the CDC’S MERS response effort.

To the confusion and frustration of a number of scientists watching the outbreak from a distance, it appears Saudi Arabia — the only country to have diagnosed substantial numbers of cases — has not conducted what is known as a case control study on MERS patients.

A case control study is epidemiology 101. This type of research compares people who contract the disease to those who don’t. It is an invaluable way to start generating ideas about how people are becoming infected and what behaviours, exposures or biological traits put people at greatest risk.

Pallansch admits that when CDC disease detectives are sent to investigate an outbreak, setting up a case control study is high on the list of priority tasks.

Staff of the World Health Organization went so far as to design a template for such a study that Saudi Arabia or any other country with MERS cases could use, posting it on the agency’s website in early July. Still, the WHO’s point person for MERS, Dr. Tony Mounts, doesn’t know where things stand on the issue — and his lack of knowledge is not from lack of interest.

“I don’t know what has or hasn’t (been done). I just don’t have the information,” Mounts says. “I know they are talking to patients, I know they are gathering data. Whether they’ve done a formal study yet or not, that’s the question.”

Dr. Ziad Memish, Saudi Arabia’s deputy minister of health, did not reply to a request for an interview for this article.

Dr. Alimuddin Zumla, an infectious diseases researcher at University College London who has been tapped by Memish to help on several Saudi MERS studies, says he does not know of any case control studies on MERS that have been done, though there have been discussions about the idea.

Case reports from Saudi Arabia are bare-bones, leaving the WHO to scramble to gather relevant information. This far into an outbreak, scientists would expect to see a consistent set of facts about each case, but that hasn’t been forthcoming.

“I think that right now, it is at the stage of ’Does this data eventually become public through (scientific) publication or presentation, or is it data that does not exist?”’ Pallansch says.

Dr. John Spika, director general of the public health agency’s centre for immunization and respiratory infectious diseases, says Saudi Arabia has been reporting cases more rapidly of late, and he believes there has been a better information flow.

“It obviously could be better. They haven’t done what China did with H7,” he says, referring to H7N9, the new bird flu virus that infected roughly the same number of people as MERS has, but over four months in the late spring and winter.

Chinese scientists shared information rapidly and have pumped out a steady stream of scientific papers on the new virus. “China, what they’ve done with H7 is to me just phenomenal,” says Spika. “But then China also didn’t do so well with SARS.”

Some of the MERS knowledge gaps are the result of cultural factors. To date there hasn’t been a single reported autopsy done on a patient who has died of MERS. Autopsies are rarely if ever done in the Muslim culture.

Matt Frieman, a coronavirus expert at the University of Maryland who is looking for drugs that might work against MERS, says the lack of a single image of the damage the disease does to lungs hinders his work.

There are educated guesses on the incubation period of the disease — the time from exposure to onset of symptoms, which typically falls within a range. With SARS, some people got sick as late as 14 days after exposure; Memish said at a WHO meeting in May that with MERS it can be as long as 14.5 days.

But it’s not yet known when people who are sick are contagious, key information for trying to stop spread of a disease. With SARS, patients were only infectious after they developed symptoms, which meant isolating them and quarantining their contacts stopped the spread. It’s hoped this is true for MERS as well, but the data to prove it either don’t exist or haven’t been shared.

“Ideally we need a prospective study of all new cases where MERS-CoV” — short for coronavirus — “viral load levels are measured in all clinical samples,” says Zumla, referring to sputum, urine and stool and other specimens.

“This is the only way to say how long the infectious period lasts and what infection control measures should be in place.”

Source: The Province