No 45 - 2019

Prolonged local Listeria monocytogenes outbreak resolved

Listeriosis is a rare but serious, invasive, food-borne infection with the bacteria Listeria monocytogenes. It primarily affects immunocompromised persons, elderly people and pregnant women.

All isolates from invasive listeria infections are submitted to Statens Serum Institut (SSI) for whole-genome sequencing. In this manner, clusters of genetically related bacteria and potential outbreaks can be identified. Outbreaks are investigated by the SSI in collaboration with the Danish Veterinary and Food Authority and DTU Food.

Whole-genome sequencing has made it possible to identify a prolonged local outbreak in which the same type of listeria has been detected in six persons. The six persons fell ill in the 2016-2019 period. Five of the patients were women. All six resided in East Jutland, and the hypothesis was therefore, that the infection was caused by a product, which was not available in the rest of Denmark. 

As part of the enhanced monitoring of listeriosis, SSI conducts interviews with patients or their relatives on exposures in the month leading up to their listeriosis.

In September 2019, interviews with the latest cases made it clear that they had used the same greengrocer’s and had eaten the same type of product prepared there. Furthermore, shopping information linked one of the patients who fell ill in 2016 to the same place.

During a subsequent control visit to the company, the Danish Veterinary and Food Administration detected listeria in the food and production environment. The sequences from the listeria isolates of the patients and from the food and production environment were genetically closely related.

The company has discontinued production in accordance with an injunction issued by the Danish Veterinary and Food Administration (DVFA), and on 20 September 2019 the DVFA recommended that users discard hummus, oil-cured olives, dates and other foods with a high water activity bought at the greengrocer’s in question. No cases of this type of listeria have been registered since August 2019.

(L. Espenhain, L. Müller, S. Ethelberg, Department of Infectious Disease Epidemiology and Prevention, S. Schørring, Department of Bacteria, Parasites and Fungi, T.B. Nielsen, the Danish Food Inspection Unit Northeast , DVFA)

Supply problems affecting the HPV vaccine Gardasil 9 not forming part of the childhood vaccination programme

The pharmaceutical company MSD has notified that they are unable to supply the Gardasil 9 HPV vaccine to the private market until 2021. Even so, the supply of HPV vaccine to the childhood vaccination programme is secured and will therefore not be affected.

The pharmaceutical company MSD that produces the HPV vaccine Gardasil 9 has notified that they expect supply problems affecting the availability of this vaccine as from November 2019 and throughout 2020 for vaccination not forming part of the childhood vaccination programme. The cause is a rise in global demand for the vaccine. Therefore, production cannot meet demand.

Vaccines will still be available for the Danish childhood vaccination programme

Even so, the supply shortage will not affect the vaccines previously earmarked for the childhood vaccination programme. MSD has made it clear that Gardasil 9 will be supplied to Statens Serum Institut despite the shortage. Thus, all boys and girls comprised by the childhood vaccination programme may receive the vaccine as planned.

A shortage of HPV vaccines is expected for vaccines given to people not covered by the childhood vaccination programme

The shortage of vaccines affects only the supply of vaccines for vaccination not covered by the childhood vaccination programme, i.e., for persons who themselves opt for vaccination and defray the associated costs themselves as they are not covered by the programme.

MSD expects that pharmacies - the primary sales channel for vaccines not covered by the childhood vaccination programme - will shortly be out of Gardasil 9 stock. It is expected that supply to the private market may, to some extent, be covered by parallel imports of Gardasil 9, but it is currently not known if the demand will be met in full throughout the shortage period. MSD also informs that they do not expect their provision of Gardasil 9 to have normalised until early 2021.

Persons not covered by the childhood vaccination programme risk having to wait for their vaccination

Persons who are currently receiving a patient-paid HPV vaccination series have already achieved some level of protection. Due to the expected supply shortage, these people may need to postpone the outstanding part of their vaccination series.

While a shortage of vaccines persists, the SSI assesses that HPV vaccination in persons not covered by the childhood vaccination programme should be initiated only in special cases.

When assessing who may initiate vaccination due to special circumstances, the doctor should consider:

• if the person in question belongs to a group that is at special risk of developing HPV-associated cancer (e.g. men who have sex with men and immunosuppressed persons)

• the time of vaccination relative to sexual debut, as the preventive effect of vaccination generally recedes thereafter.

(P.H. Andersen, Department of Infectious Disease Epidemiology and Prevention)