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Public Health England reported that four cases of Zika infection in travellers returning from affected areas have been diagnosed in the UK since the start of the year.
All our previous output on this subject can be seen here.
Dr Nathalie MacDermott, Clinical Research Fellow, Imperial College London, said:
“’That the number of UK travellers who have tested positive for Zika virus has increased slightly is not surprising and some more cases can be anticipated in returning travellers from areas where Zika virus is present and there is a large presence of Aedes mosquitoes. This does not alter the risk or advice given to the UK public previously. As the Aedes mosquito is not present in the UK there is very minimal risk of transmission to the UK public who have not travelled to regions where Zika virus is present.
“The advice provided by Public Health England should be followed which is that returning travellers who develop symptoms that may be consistent with Zika virus infection should seek medical attention and inform the health care professional that they have been in a country where Zika virus is present so that appropriate measures for testing can take place if required. Male travellers returning from affected countries whose partners are pregnant or who could become pregnant should use barrier contraception (condoms) for a minimum of 28 days on their return and if they have had an illness consistent with symptoms of Zika virus or have tested positive for Zika virus they should use barrier contraception for a minimum of 6 months following their return. If a male traveller is unclear if they have been infected with Zika virus they should discuss with a healthcare professional prior to engaging in unprotected sexual activity with women of child bearing age who are at risk of becoming pregnant.”
Dr Michael Brown, Hospital for Tropical Diseases and London School of Hygiene & Tropical Medicine, said:
“Zika virus is now widespread through South and Central America, and we expect to have many more people returning to the UK having been bitten by mosquitoes that carry the virus.
“Zika is not a major health risk except in pregnant women, and non-pregnant people who have had a short illness during or shortly after their trip should feel reassured that they are very unlikely to come to any harm.
“Although there have been possible cases of sexual transmission, meaning that it could theoretically be passed on to a female partner from a man who has recently had the infection, the absence of the Aedes mosquito here means that we will not see a Zika epidemic in the UK.”
Prof. Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said:
“Whilst people are travelling to the UK from areas with active Zika virus outbreaks there will always be the risk that we will see Zika virus infections diagnosed here. But that does not mean that we are precariously balanced on the edge of a major UK outbreak. There is a very small risk that the virus can be passed on by the sexual route, so sexual partners of those infected are potentially at risk, and this should be a concern for pregnant women because of the potential association of Zika infection and development of birth defects. That’s why the advice is not to have unprotected sex when returning from one of the affected areas if a female partner is at risk of getting pregnant, or is already pregnant.
“The risk of wider transmission is even more remote because we don’t have the mosquitoes that the virus needs for spread, and our climate is too hostile for them to survive here.
“There are so many unknowns around Zika virus. Where exactly in the world are outbreaks likely to happen? How does the virus survive in those countries where it is present – is it hiding away in animal reservoirs or simply surviving on human-mosquito transmission? Once infected are we immune from future infections for life? If it does cause microcephaly when is a pregnant woman most at risk? Can we easily develop a vaccine to protect at-risk people, including travelers? Until we have answers to these questions we will never be able to predict with any accuracy what might happen in future.”
Prof. Paul Hunter, Professor of Health Protection, UEA, said:
“The current Public Health England advice on testing is that all patients who currently have Zika-like symptoms (that began whilst in an affected country or within two weeks of leaving) and are pregnant have a blood and urine test. Patients with current symptoms (that began whilst in an affected country or within two weeks of leaving) who are not pregnant have just a blood test. Patients who report having had Zika-like symptoms in the past are not offered any tests. Having said that a substantial proportion of people with Zika as with all the other flaviviruses are likely to be asymptomatic. We don’t yet know what risk if any would be associated with an asymptomatic infection during pregnancy.”
Prof. Michael Bonsall, Professor of Mathematical Biology at the University of Oxford, said:
“While there are four cases of Zika amongst travellers returning to the UK, this is an extremely low proportion of people returning to the UK after visiting the Americas. Furthermore, this virus is essentially spread by mosquitoes which associate closely with humans such as Aedes aegypti. There is no evidence that the 15 species of Aedes found in the UK (which do not include Aedes aegypti) are vectors of this virus.”
* https://www.gov.uk/guidance/zika-virus
Declared interests
Dr Nathalie MacDermott: “I am a paediatrician. I am also undertaking a PhD in Ebola virus disease at Imperial College London funded by the Wellcome Trust.”
Dr Michael Brown: “No conflicts.”
Prof. Jonathan Ball: “No conflicts of interest.”
Prof. Paul Hunter: “I have no conflicts of interest.”
Prof. Michael Bonsall: “I was the Specialist Adviser to the inquiry on Genetically Modified Insects by the House of Lords Science and Technology Committee, and am a member of ACRE (Defra’s committee on releases into the environment). The Advisory Committee on Releases to the Environment is independent scientific committee that through EU derivatives and national UK legislation is mandated to provide the UK government/ministers with advice on the environmental risks (to wider receiving environments/human health) of non-native and GM releases. I have been a member of this committee since December 2007. I have carried out occasional consultancy work for WHO, NIH, and EFSA, including work on GM-based control methods for mosquitoes. I have received research funding from BBSRC (including working with Oxitec on GM insects), Oxford Martin School, NERC, the Royal Statistical Society, and the Royal Entomological Society. For full details of all my interests, please see: http://www.parliament.uk/documents/lords-committees/science-technology/GMInsects/michael-bonsall-specialist-adviser-interests.pdf”