No 10 - 2013

Update on new coronavirus outbreak

In September 2012, two patients, one from Saudi Arabia and another from Qatar, were diagnosed with a new coronavirus (NCoV). The patients had suffered from severe airway infections, and the national and international health authorities and organisations therefore reacted promptly, i.a. by initiating measures to diagnose and monitor the new virus. By 6 March 2013, the WHO had reported a total of 13 confirmed cases of NCoV.

Symptom onset in these 13 cases occurred from April 2012 to February 2013, and seven of these patients have since died.

Coronaviruses are a family of RNA viruses found in birds and mammals. Coronavirus is a common cause of cold, but may also — in rare cases — give rise to lower respiratory infections. There are several groups of coronavirus, and the virus causing the 2003 SARS epidemic is a special variant. NCoV belongs to the same group as SARS, but the two are genetically different. NCoV is similar to the coronaviruses found in bats.

Prior to symptom onset, a total of eight cases had either resided or travelled in Qatar or Saudi Arabia. Among these were a family cluster counting three cases in Saudi Arabia. In April 2012 an outbreak of severe pneumonia occurred in a hospital in Jordan. Two of the cases involved were fatal and have subsequently been confirmed as NCoV infections.

On 11 February 2013 the British Health Protection Agency confirmed NCoV in a British citizen who had travelled in Pakistan and the Middle East. He fell ill on 24 January 2013 and returned to England on 28 January, still feeling unwell. He briefly stayed in his home before being admitted to hospital.

Two family members with no travel history subsequently developed symptoms and tested positive for NCoV. One of the two family members was admitted to hospital and died; this person suffered from previous chronic disease.

The other family member, who had only briefly come into contact with the patient at the hospital, developed mild symptoms and recovered without admission. For the three English cases, active contact tracing was performed among family members and healthcare professionals; no further cases were detected.

Contact tracing comprises serological investigations with a view to deciding if asymptomatic infection has occurred.

Person-to-person transmission may have occurred in four of the 13 reported cases. Furthermore, contact tracing was performed among more than 200 contacts to confirmed cases in the Middle East and Europe; no signs of infection were found. Consequently, the epidemiological pattern seems to indicate that person-to-person transmission is limited.

Denmark was among the first countries to develop diagnostic tests for NCoV, but although several patients have been tested in Denmark, no cases have been detected at present. However, physicians should still keep NCoV in mind for patients with severe lower respiratory tract infection who have stayed on the Arabic Peninsula or neighbouring countries within the ten-day period preceding symptom onset.

(F. Dorleans, T.G. Krause, Department of Infectious Disease Epidemiology)

Registered age range for Japanese encephalitis and meningitis vaccines extended

The age range for the registered Japanese encephalitis vaccine (Ixiaro®) has been extended by the European Medicines Agency (EMA). The vaccine may be administered as from two months of age as two doses given at a 28-day interval. Children aged 2 months to 3 years should receive half the normal dose. The registered age indication replaces the previous off-label recommendation, EPI-NEWS 37/09.

Vaccination is normally recommended only for prolonged stays, i.e. stays exceeding four weeks, in Asia where Japanese encephalitis occurs, and for stays in rural areas in particular, EPI-NEWS 27/12.

For more information on vaccination of children before visits to developing countries, see EPI-NEWS 6/11. Revaccination is recommended 12-24 months after the primary vaccination, depending on the degree of exposure, EPI-NEWS 25/10.

Two tetravalent conjugate vaccines have now been registered for protection against meningococcal disease caused by group A, C, Y or W135; Nimenrix® and Menveo®.

Nimenrix® can be used for children aged > 1 year of age and for adults. The vaccine is administered as a single dose.

The previous Menveo® formulation may be used for children aged 11 years or above and for adults. The vaccine is administered as a single dose. The EMA has recently approved an extended age indication for a new formulation of Menveo®, which allows the vaccine to be given as from two years of age.

Presently, however, this formulation is not available via the SSI. Until further notice, SSI therefore recommends that children aged 1-10 years of age receive the registered Nimenrix® vaccine, see above. It is currently not known if and when revaccination is needed.

If indicated, children aged 2 months to 1 year may receive primary vaccination in the form of two Menveo® doses given at a 1-month interval. The Danish Medicines Agency (now the Danish Health and Medicines Authority) has previously assessed that the vaccine may be used off-label in this age-group.

In case of continued risk of exposure, a booster dose is given 12 months after the primary vaccination programme. Vaccination of children aged from 2 months to 1 year should be limited to cases in which administration of the four-valent vaccine (Menveo®) is indicated. In cases which only call for group C-protection, the registered, monovalent conjugate vaccine (NeisVacC®) should be preferred.

Vaccination with the tetravalent meningococcal vaccine is recommended for stays in African countries in which meningococcal disease is periodically endemic, see EPI-NEWS 27/12 and www.ssi.dk/rejser (in Danish). Additionally, the vaccine may be used for outbreak control following assessment by the Medical Officer of Health, EPI-NEWS 38/12.

(P.H. Andersen, on behalf of the Consultancy Team, Department of Infectious Disease Epidemiology)

Two measles cases notified in February 2013

In February, another two measles cases were notified. The year's first case was notified in January, EPI-NEWS 5/13.

The second case was a 37-year-old woman from Zealand, presumably infected during vacations in Thailand. The woman had probably been MMR-vaccinated once at the age of 15 years.

It is well known that measles may occur despite previous MMR vaccination, and this case underlines that the risk of measles should be taken into account when providing medical pre-travel advice, in line with other travel-associated diseases such as hepatitis A and yellow fever, among others.

The third case was a 19-year-old unvaccinated man from the Central Jutland Region, who had no recent travel activity or known contact with any measles case.

It has not been possible to establish an epidemiological link to the first case in January although the first case had stayed in the same area, but the latter case occurred within the 7-18-day incubation period and brief, accidental contact therefore cannot be excluded.

Physicians are still encouraged to pay particular attention to the diagnosis in children and younger adults who present with measles symptoms. It is important that persons suspected of having measles avoid being in waiting rooms with other patients, as measles is extremely infectious.

Vaccination against measles is covered by the MMR vaccine which is offered to all children via the Childhood Vaccination Programme. The vaccine may also be given to adults who have not previously been vaccinated. Adults, however, pay for the vaccine themselves as the temporary offer of free MMR vaccination of young adults ended as per 31/12 2012.

In case of definite exposure of non-immune persons, MMR vaccination may be given within three days or immunoglobulin injection within six days to prevent or lessen the effects of the disease.

(P.H. Andersen, L.K. Knudsen, Department of Infectious Disease Epidemiology)

Link to previous issues of EPI-NEWS

6 March 2013