The UK Health Security Agency’s (UKHSA) latest data indicates that travel-associated mosquito-borne infections are returning to pre-pandemic levels. This includes infections such as dengue and malaria, which can cause severe disease, and highlights the need for travellers to take precautions to reduce health risks while abroad. Cases were confirmed in parts of the UK in individuals who had recently been abroad.
In 2023, 634 dengue cases were reported in returning travellers across England, Wales and Northern Ireland, aligning closely with those in 2019, during the pre-pandemic period, when 790 cases were reported. During 2023, most reported cases of dengue were acquired in Southern Asia and South-Eastern Asia, particularly India. However, there has been an increase in cases acquired in Central America and the Caribbean, due to recent outbreaks in these parts of the world. The World Health Organization reports a significant rise in global dengue cases in 2023, resulting in over five million cases and 5000 deaths worldwide.
A total of 1,637 malaria cases were confirmed in England from January to October 2023. Cases returned to pre-pandemic levels, similar to the 1,719 cases reported in the UK in 2019 and matching closely with the average of 1,612 cases reported between 2010 and 2019. The World Health Organisation reports that in 2022, global malaria cases were estimated at 249 million, surpassing pre-pandemic levels by 16 million compared to 2019.
Eight Zika cases were reported in England in 2023 – a similar level to 2022. Case numbers peaked in 2016 with 725 cases, reflecting the Zika outbreak in America that year, before decreasing in the following years. While cases of Zika are low, the infection poses a particular threat to pregnant women and those trying to conceive.
Symptoms of mosquito-borne infections include fever, severe headache, pain behind the eyes, in muscles, joints and abdomen, loss of appetite, nausea and vomiting.
The Travel Health Pro website, supported by the UK Health Security Agency, has information on health risks in countries across the world and is a one-stop-shop for information to help people plan their trip abroad. Ideally travellers should consult their GP, practice nurse, pharmacist, or travel clinic 4 to 6 weeks before their trip for individual advice, travel vaccines and malaria prevention tablets, if relevant for their destination.
In countries with insects that spread diseases like dengue, malaria or Zika, travellers can protect themselves by using insect repellent, covering exposed skin, and sleeping under a treated bed net where air conditioning is not available.
A live, attenuated (weakened) dengue vaccine called Qdenga®▼ is licensed in the United Kingdom (UK). The Joint Committee on Vaccination and Immunisation (JCVI) Travel Sub-Committee (TSC) has recently advised individuals aged 4 years of age and older with confirmed dengue infection in the past and who are planning to travel to areas where there is a risk of dengue infection consider private vaccination. Travellers can discuss the vaccine and their eligibility with their local travel health clinic.
Dr Philip Veal, Consultant in Public Health at the UK Health Security Agency, said:
As travel has increased following the lifting of travel restrictions during the pandemic, so have serious mosquito borne infections. There are simple steps that people can take to reduce the risk of infections such as malaria, dengue and Zika. Prevent mosquito bites by using insect repellent, covering exposed skin and sleeping under a treated bed net. Plan ahead and visit the TravelHealthPro website to look up your destination and the latest health information and advice. Even if you have visited or lived in a country before, you will not have the same protection against infections as local people and are still at risk.
Dr Dipti Patel, Director of the National Travel Health Network and Centre, said:
If you are making plans to travel abroad this year, please take a moment to prioritise your health and plan ahead. Check the relevant country information pages on our website, TravelHealthPro, and ideally speak to your GP or a travel health clinic 4-6 weeks ahead of travelling to ensure you have had all the necessary vaccinations and advice you need to ensure your trip is a happy and healthy one. When you return to the UK, if you feel unwell, seek medical attention and ensure you inform your healthcare provider that you have been travelling recently.
It is also important for travellers to:
- Ensure your routine childhood vaccines are up to date
- Stock up on necessary medications
- Get valid travel insurance to cover your entire trip and planned activities
NaTHNaC and the UK Health Security Agency (UKHSA) have recently reviewed destination-specific guidance for countries with a known or possible risk of Zika virus. Zika virus infection is usually a short-lived flu like illness, sometimes with a rash and itchy skin, severe disease is unusual. However, while serious complications and deaths from Zika are rare, infection in pregnancy can cause birth defects. There is no drug or vaccine to prevent Zika. The only way to try and prevent infection is by minimising mosquito bites or by avoiding visiting regions with a known or potential Zika risk.
Importance of MMR vaccination
UKHSA is also reminding travellers to be aware of other checks they should do to ensure safe travels. Ensuring all members of your family, especially children, are vaccinated against measles with both doses of MMR is vitally important – especially if travelling to countries where measles cases are high, including parts of Europe.
There is concern that the high probability of importation from other areas experiencing high circulation could worsen the ongoing outbreak in England. It’s possible that the seasonal peak of the virus is also yet to be seen in the coming months.
The World Health Organization recently repeated their warning on the growing measles threat due to sub-optimal vaccination rates well below the 95% target, highlighting that more than half the world faces high measles risk.
It is known that hundreds of thousands of children in England are still not fully vaccinated against measles and are at risk of serious illness or lifelong complications, but measles is completely preventable with vaccination. The current childhood vaccinations campaign is reminding parents of the importance of ensuring their children are vaccinated on time. Parents should check their child’s Red Book now to ensure that children have had their MMR and other routine vaccines. If they are unsure, they should get in touch with their GP practice, and if needed, their child will be brought up to date. They should respond as soon as possible if the NHS is in touch to catch up. This is especially important if they are planning travel to countries that are currently seeing a high number of cases and will prevent them from spreading measles to others while traveling too.
