Wednesday, March 16, 2016

The MERS Outbreak in Buraidah, Saudi Arabia, February - March 2016

Since late February, a Middle East Respiratory Syndrome (MERS) outbreak has been occurring in northcentral Saudi Arabia in Buraidah in the Al Qassim region. Through March 16, 2016, there have been 23 MERS cases reported from Buraidah by the Saudi Arabia Ministry of Health (SAMOH), include 6 females and 17 males, ranging in age from 22 to 84 years. Six of the cases are healthcare workers. Based on reports by the SAMOH, 11 of these individuals have died. Only five individuals have been reported to have recovered.

Constructing a preliminary timeline of Buraidah outbreak

Details are only available from the World Health Organization (WHO) for 18 of these cases prior to March 10, 2016. (link, link)

At least five of the cases reported by WHO appear to be community-acquired infections which suggest that MERS may be wide-spread in the Buraidah community. These individuals include a 40 year-old male (WHO 1670) who experienced symptoms on February 22 and was hospitalized the same day. It is not clear how this individual became infected. At least four other community-acquired infections also occurred. The first is a 42-year-old male (WHO 1658) who had symptoms on February 26 and was hospitalized on March 4 and is reported to have contact with animals. A 67-year-old female (WHO 1668) developed symptoms on February 28 and was hospitalized two days later on March 1. Investigations of exposure to known risk factors for this case are continuing. A 68 year-old female (WHO 1655) experienced symptom onset on March 2 and was hospitalized on March 5. Investigations of exposure to known risk factors prior to symptom onset is currently ongoing for this individual as well. The fifth individual is a 50-year-old male (WHO 1684) who experienced symptom onset on March 1 and was hospitalized the same day. He is reported by the SAMOH to have died.

Thirteen of the remaining WHO-reported MERS cases, including three healthcare workers, appear to be associated with the nosocomial outbreak at a hospital in Buraidah. The first healthcare worker developed symptoms on February 28 and the second on March 3. The third healthcare worker developed symptoms on March 6. This indicates that the coronavirus was present in the hospital prior to February 28.

According to the WHO report, eight of the confirmed cases were being hospitalized or treated in the Buraidah hospital starting as early as February 4 (seven had comorbidities and were possibly being treated for these conditions) and continuing through the start of the hospital outbreak. Three of these hospitalized cases initially tested negative for MERS; one on February 20, and two on February 24. Later all three of these individuals tested positive on March 4, indicating that these cases may have been infected after February 20.

This suggests that the possible index case for the hospital outbreak is the 40-year-old male (WHO 1670) who was experiencing symptoms on February 22 and was hospitalized on same day. He died on March 4. The other four community-acquired cases discussed above were hospitalized between March 1 and March 4, too late to have infected the first health care worker and some of the other hospitalized cases.

Between March 11 and March 16, the SAMOH identified five additional MERS cases from Buraidah. The WHO has not yet reported the details of these cases, but all least two or three of these cases appear to be part of the nosocomial outbreak.


Although the details are unclear, community-acquired MERS infections are occurring in Buraidah  along with a nosocomial outbreak that originated after February 20 in a local hospital. In the Buraidah outbreak almost half of all of the reported fatalities (5 out of 11) are under 35 years in age. This is a high percentage. Of the previously reported MERS fatalities from Saudi Arabia only about 10% are under the age of 35.

It is not clear if the nosocomial MERS outbreak in Buraidah has been contained.