No 25 - 2010

Revised recommendations for travel vaccination

As in the past four years, a reference group has revised and updated the SSI country-specific recommendations for malaria prophylaxis prior to travels abroad. The country-specific recommendations will be published in an upcoming edition of EPI-NEWS.

In 2010, the following changes apply:

Yellow fever

- Australia: Requirements for travellers > 1 year of age who have passed at least one of the previous six nights in a country where there is risk of transmission, excluding the Galapagos Islands (Ecuador) and limited to the Missiones province of Argentina.

- Bolivia: Vaccination is required when travelling to certain parts of the country.

Guinea-Bissau: Vaccination is required for all travellers > 1 year.

- French Polynesia and Tonga: No longer any requirements for travellers arriving from transmission risk countries.

- Brazil: Yellow fever vaccination is not a requirement, but vaccination is recommended for substantial parts of the country.

Japanese encephalitis (JE)

I September 2009 a newly approved JE vaccine was marketed (Ixiaro®), EPI-NEWS 37/09. The primary vaccination series consists of two vaccines which should be given at a four-week interval.

The European Medicines Agency has recently established guidelines for the Ixiaro® booster dose which should be administered 12-24 months after the primary series if JE exposure persists.

The duration of the protection provided by the booster dose remains unknown. However, no results suggest that its duration is shorter than the three years observed for the remaining JE vaccines.

In the winter and spring of 2010, the vaccine has seen production and supply issues, EPI-NEWS 3/10. Ixiaro® is currently in stock, but future supply problems cannot be excluded. In such cases, SSI may supply a non-approved JE vaccine. For a period, SSI has therefore stocked and sold the GCC® vaccine.

The two JE vaccines are identical with regard to antigens and the main difference between them is the cell lines used to culture the virus. Currently, cross-administration of Ixiaro® and the previously used vaccines remains undocumented and unapproved. This applies to primary vaccination as well as booster doses. The JE vaccination recommendation for stays with duration of four weeks or more in the transmission zone is merely instructive. Normally, risk only occurs in connection with stays in rural areas with swine farming and wading birds. Even long-term stays in urban areas will normally not be associated with any risk. In case of intense exposure or knowledge of ongoing outbreaks, stays shorter than four weeks may justify vaccination.

Hepatitis A and B

At EU level, the Ambirix® vaccine has achieved marketing approval for treatment of hepatitis A and B as a two-dose regime in children aged 1 to 15 years. This vaccine is not currently marketed in Denmark, but its contents are identical to that of Twinrix Adult® used for persons aged > 15 years.

Where immediate protection against hepatitis A and future protection against hepatitis B is needed in 1-15-year-old children, Twinrix Adult® may be administered twice at a 6-12 month interval as an alternative to the standard three-dose Twinrix Paediatric®regime.

The standard three-dose regime provides a more rapid seroconversion for hepatitis B than the two-dose regimen and should be preferred when hepatitis B prophylaxis is needed for an upcoming journey. Both doses should be administered before initiating the journey. The achieved hepatitis B protection is the same for the two regimes (nearly 100%) once the final dose has been given. Hepatitis A protection after the first dose is given is also identical and nearly complete for both regimens.

Meningitis

Production of the previously used sero group A and C vaccine (Meningovax®) will be discontinued. Once the remaining stock has been dispensed, the unregistered four-valent meningitis vaccine (Mencevax®) will be available until further notice. This vaccine provides protection against serogroups A, C, Y and W135. Previously, Mencevax® was only indicated for pilgrimage to Mekka, but in future it will also be relevant for travels to other areas, where meningitis vaccination is recommended, primarily to the Sahel belt of Africa. Children below the age of two years achieve some protection against sero group A, but not against the remaining three sero groups.

(M. Buhl, Soc. of Travel Med., S. Thybo, Soc. for Inf. Dis., J. Kurtzhals, Soc. for Clin. Microb., N.E. Møller, College of GPs, L.S. Vestergaard, Soc. for Trop. Med., & Int. Health, K. Gade, Paed. Society, P.H. Andersen, Dept. of Epidemiology)

Salmonella outbreak caused by salami

In May, an outbreak of Salmonella Typhimurium was detected. By MLVA typing, it was determined that the outbreak had a special DNA profile. April and May saw a total of 19 cases of this special type of salmonella. Patients were mainly from the Copenhagen area and relatively young; the median age was 20 years (range 1-69 years).

None of the affected patients had travelled abroad or participated in joint eating arrangements where they could have been infected. When interviewed, two parents of the infected children stated that the children had ingested the salami product “Minimum Spegepølse med Hjortekød” from the supermarket chain Netto. Further interviews and shopping receipts of other families with infected children showed that 16 of the 19 infected children had ingested the same salami type. Preliminary results from a case-control study show a substantial association between ingestion of the salami and disease symptoms (unadjusted odds ratio of 70).

The salami was produced in Germany and contained a mix of New Zealand deer and EU pork. The relevant shipment of salami was probably sold in the supermarket in the period end March to beginning of May. When the epidemiological investigation identified the salami as the cause, the relevant consignment was already sold out. Consequently, the salami was not tested for salmonella.

Since 17 May, SSI has diagnosed no further cases of the salmonella type seen in the outbreak, which seems to have ended. Nevertheless, the Veterinary and Food Administration has issued a warning to citizens advising against eating the salami in question bought in the period from March to May 2010.

(K.G. Kuhn, S. Ethelberg, Dept. of Epidemiology, M. Torpdahl, Dept. of Microbiol. Surv. & Research)

Statement from the National Board of Health

Executive order on free influenza A (H1N1) vaccination for selected population groups is extended to

30 September 2010. Executive order no. 1005 of 27 October 2009 therefore applies to vaccinations performed before 30 September 2010, and vaccination sites which stock vaccinations should keep these until this date. The A (H1N1) vaccine forms part of this year's seasonal influenza vaccine, which is expected to be available as from 1 October 2010.

Individually notifiable diseases and selected laboratory diagnosed infections  

23 June 2010