|Posted on 11 October, 2019 at 0:55|
The spread of the dengue virus is highly reported as rapidly increasing in many Asian countries in particular. Last week Bangladesh and Pakistan reported high levels of outbreaks exceeding the number of beds and medical facilities available to treat these patients. These countries are in addition to those reporting earlier in the year such as Philippines, Indonesia, Taiwan and India.
In an article published last week there are references from France and Spain of patients returning home after contracting dengue abroad and a call for a rapid risk assessment process in case autochthonous cases develop.
Although currently the levels of the transmitting mosquito, Aedes albopictus, are low in Southern Europe, the impact of global warming and the climate is indicating a potential of this mosquito moving further north in the forthcoming years. In the USA for example the last 2 years have had reports of dengue in Florida and this year is the same with CDC recording watch levels on the infection.
So what about the vaccine. We know about the suspended vaccinations in the Philippines where it was concluded that the vaccine could only be given to patients with a laboratory confirmed result of previous infection. With the disease having 4 serotypes and no cross protection (ie contraction of type does not give protection against types 2,3 and 4) then for full protection a patient would need to contract dengue up to 4 times. With the disease showing that it can also produce 2 further conditions of dengue haemorrhaging fever and severe dengue. This is unlike other viruses of the same family such as zika and chikungunya.
With increasingly low air fare costs to infected countries and the only protective advice is the daytime use of insect repellents, is there the risk of a UK traveller returning with dengue increasing?
With the EU licensing the use of dengue vaccine for clinically assessed patients, should the MHRA now be considering the introduction of the vaccine for use in travellers resident in the UK and travelling to endemic areas, such that we have an established set of trial data that will be available should the infection ever mutate and survive in the UK weather conditions.