A new report authored by members of WHO-led international investigation team and published by the New England Journal of Medicine on Wednesday, June 19, entitled Hospital Outbreak of Middle East Respiratory Syndrome Coronavirus says that the novel coronavirus known as Middle East Respiratory Syndrome (MERS) that is known to have infected 64 people in the Middle East (mostly in Saudi Arabia), thus far killing killed 38 of them, now appears to be a serious risk to hospitals where it evidently transmits easily.
MERS shares some similarities with the SARS virus that caused a worldwide epidemic and claimed 916 lives in 2002-2003, but it is caused by a different type (“Lineage C”) of coronavirus (MERS-CoV) that was identified in September 2012, before the current outbreak began. MERS was first identified in Saudi Arabia and Jordan, and cases have been reported in Qatar, the United Arab Emirates and Tunisia, as well as a few having been imported into France, Britain and Italy.
Both coronaviruses seem to share the same two to ten-day interval between exposure and the onset of symptoms; both cause fever and cough, and in some instances diarrhea; most cases of both are severe to lethal, and both have spread in hospitals to other patients in multiple chains of person-to-person transmission, and with spread between hospitals occurring when a patient is moved from one institution to another.
However, compared with SARS, with which otherwise healthy individuals became afflicted with severe, sometimes fatal cases of the disease, severe MERS cases have thus far manifested mainly in older males with underlying disease conditions — a profile representing 75 percent of the 23 cases described in the NEJM paper, and while as with SARS there has been some spread from patients to health care workers with MERS, the latter has proved less lethal.
The NEJM report (DOI: 10.1056/NEJMoa1306742) this week notes that Between April 1 and May 23 of this year, a total of 23 cases of MERS-CoV infection had been reported in the eastern province of Saudi Arabia. Symptoms included fever in 20 patients (87%), cough in 20 (87%), shortness of breath in 11 (48%), and gastrointestinal symptoms in 8 (35%); while 20 patients (87%) presented with abnormal chest radiographs. As of June 12, a total of 15 patients (65%) had died, six (26%) had recovered, and two (9%) remained hospitalized. The median incubation period for these cases was 5.2 days.
A total of 21 of the 23 cases were acquired by person-to-person transmission in hemodialysis units, intensive care units, or in-patient units in three different health care facilities, and among 217 household contacts and more than 200 health care worker contacts identified, MERS-CoV infection developed in five family members (three with laboratory-confirmed cases) and in two health care workers (both with laboratory-confirmed cases).On May 14, CTV News reported that the Saudi Ministry of Health has confirmed the two health-care workers’ ( identified by other news outlets as nurses) infections, marking the first incidence in this nascent epidemic of health personnel being infected. SARS took a relatively heavy toll on health care workers in 2003, including several in Toronto, Canada.
SARS-CoV was transmitted from person to person mainly through respiratory droplets that are produced when a person sneezes or coughs and also through direct contact with a surface contaminated with infected respiratory droplets. “Once we figured out that infection control worked to stop the transmission, people started to get serious about it,” University of Texas Medical Branch epidemiologist and virologist Dr. Thomas Ksiazek, told ABC News in May. Dr. Ksiazek, who is Director of the National Biocontainment Training Center (NBTC) and a professor in the department of pathology at the University of Texas Medical Branch in Galveston, and who served as chief of the U.S. Centers for Disease Control and Prevention Special Pathogens Branch during the 2003-’04 SARS outbreak recalls that “We were pretty lucky, but the key was infection control and mindfulness,” noting to ABC that “mindfulness” will be key once again in containing the current outbreak since a vaccine for nCoV could take years to develop and test.
Watch this ABC News video for a detailed look at the MERS virus:
They also observe that “the rapid transmission and high attack rate in the dialysis unit raises substantial concerns about the risk of health care–associated transmission of this virus,” as does the variability of transmission risk, many infected patients not transmitting disease at all, while one patient passed the disease along to seven others, reminiscent of SARS’ erratic transmissibility. While most people who became infected with SARS passed the virus to nobody or perhaps one other person, some SARS patients were “superspreaders” who infected large numbers of people — one Singapore patient infecting 62 others, and a woman in Toronto, who didn’t become seriously ill herself, infected 44 other individuals with the virus, including three admission clerks, a security guard, five visitors, three nurses and one housekeeper at a hospital within a 2 1/2 hour span of contact.
The Baylor College of Medicine Department of Molecular Virology and Microbiology information profile notes that one reason that SARS-CoV (and presumably MERS-CoV) might be more lethal than other coronaviruses is that it appears to interfere with an enzyme system in humans that is critical for regulating body fluid balance. Consequently, the virus could disrupt normal functioning of the lungs by blocking this enzyme system and allowing fluid to leak into the air sacs of the lungs, resulting in severe respiratory illness, adding that “Despite the large amount of knowledge that has been gained about SARS-CoV following the  outbreak, there are still no vaccines or antivirals approved for preventing or treating SARS-CoV infections.”
Or MERS-CoV infections.
Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, noted to Houston Chronicle SciGuy blogger Eric Berger this week that while there’s a lot researchers don’t know about the new MERS-CoV virus, but what they do know is that mortality — some 60 percent — has been pretty high, but with the caveat that milder cases of the disease may not be getting reported, so it’s difficult to get a handle on the actual mortality rate so far.
He also observed that while evidence indicates that MERS is transmissible from person to person, up to now the rate has been low, although that doesn’t mean the virus can’t mutate, and could become much more easily transmissible within a couple of months. However, Dr. Hotez advises that we should not worry too much about MERS-CoV — at least not yet. “It’s a delicate balance, you want to raise an appropriate level of concern, but you don’t want to make people overly worried,” he told Berger. “In Texas a far bigger concern would be diseases such as West Nile Virus, which in a surprisingly strong outbreak in 2012 killed 89 people.
However, as Scientific American’s Helen Branswell noted in a June 7 article, the Muslim month of fasting, Ramadan, begins July 9. with as many as two million people from around the globe expected to make umrah pilgrimages to holy sites of Saudi Arabia, and infectious disease control at mass gatherings a challenge at the best of times, which mid-2013 definitely isn’t in the context of the MERS-COV outbreak. And come fall will be the even larger hajj pilgrimage to Mecca, this year expected to fall between October 13-18 (because the Islamic calendar is a lunar calendar, eleven days shorter than the Gregorian calendar used in the Western world, the Gregorian date of the Hajj changes from year to year). In a Canadian Press report last March, Helen Branswell cited Dr. Kamran Khan, who tracks global travel patterns as a tool to predict and interpret spread of diseases, noting that about 25 percent of people who travel from Saudi Arabia, Qatar and Jordan — all of which have reported MERS-CoV cases — go to massively populated countries of South Asia like India, Pakistan and Bangladesh. Ms. Branswell also quotes Michael Osterholm, director of the Center for Infectious Diseases Research and Policy at the University of Minnesota, commenting: “These RNA viruses [Coronaviruses are RNA viruses, which mutate rapidly] you just can’t predict what they’re going to do. So the longer they stay in the human population, the more likely it is they’re going to do something that’s not good.”
If MERS becomes more easily transmittable, and begins to spread globally with umrah or hajj pilgrims returning from Saudi Arabia, possibly including some superspreaders, that will be the time to start worrying.
Read our Peter Hotez info page at BioNews Texas