Why and how the guidance for Zika virus is changing


In 2015, an outbreak of Zika virus made headlines around the world due to its link to an increase of the number of babies born with microcephaly – a smaller head than expected, which can be due to abnormal brain development. This was particularly prominent in Brazil but cases were seen in other countries across South America, the Caribbean and Asia.

Zika causes mild or no symptoms in most infected people. The main way people get infected is being bitten by a mosquito which has Zika, although it can also be transmitted through sexual contact, so following the outbreak PHE introduced guidance for UK travellers going to countries at risk for Zika virus transmission.

Three years on, our understanding of the virus and its sexual transmission has developed, so PHE is changing its guidance to reflect this.

What is changing?

PHE advice for those people travelling to affected countries has changed.

PHE is now recommending that if a male partner has travelled, couples should wait three months (rather than the original six) to conceive. PHE recommends consistent use of effective contraception and barrier methods during and after travel for this period, even in the absence of Zika virus symptoms.

Our guidance continues to highlight that couples considering pregnancy should consider the Zika risk in countries prior to travel and to make informed decisions about whether they indeed wish to travel to that country and/or when they can commence trying to conceive after travelling.

The terminology used to rate the risk of Zika in affected countries is also changing. Now, countries will be rated as having either a ‘risk’ or ‘very low risk’. Countries that have never reported transmission will not appear on the list, which can be seen in full on the PHE website or on the country information pages on the NathNaC website.

Advice for Pregnant women

The advice for pregnant women travelling to affected countries has been updated. The classification change mentioned above means that advice for pregnant women travelling to affected countries is now as follows:

For some ‘risk’ countries where there is the evidence of a current outbreak of Zika virus that may increase the risk to UK travellers, pregnant women should postpone non-essential travel until after the pregnancy and avoid becoming pregnant while in these countries.

In other ‘risk’ countries with less evidence of a current outbreak, pregnant women are advised to consider postponing all non-essential travel until pregnancy.

No travel advisory is provided for countries with very low risk. In all cases we advise that you check the risk for the country you are visiting.

This change gives pregnant women a broader option in deciding where and if they travel, as the recommendation to definitely postpone is no longer applied to all affected countries. Again, a list of affected countries can be seen in full on the NathNaC website.

Other travellers who are worried should visit their GP for advice and a risk assessment. We still advise all travellers to seek pre-travel health advice 4-6 weeks before their trip to a Zika affected country or area and that usual measures to avoid mosquito bites, such as nets and repellent are used.

Why have these changes been made now?

In the past three years the international community has learnt much more about Zika virus and we update our guidance on a regular basis using information from the World Health Organization (WHO), the European Centre for Disease Prevention and Control (ECDC) and the US Centers for Disease Control and Prevention (CDC), along with available  intelligence from other official sources.

We now have an improved understanding of the different patterns of transmission for Zika virus –how intense outbreaks are, why they increase and slow or seemingly go away.

This increase in knowledge means we have been able to review the advice and update all our online resources. The revised terminology will allow individuals to better understand the risks of Zika virus transmission in countries when travelling.

 Search easily for Zika guidance for all countries on the NaTHNaC website