Health advice for women returning from areas with a risk of Zika virus

This guidance contains:

1. General advice and information for women returning from areas at risk of Zika virus transmission who are pregnant or are planning pregnancy

2. Advice for pregnant women who are diagnosed with Zika virus

3. Advice for pregnant women whose baby is thought to be affected by Zika virus

This guidance provides supporting information only and does not take the place of a face-to-face consultation with a doctor or midwife. Any woman who is concerned following travel to an area where Zika virus is present is encouraged to discuss this with a healthcare professional such as their doctor or midwife.

Background

Zika virus is mainly spread by the bite of Aedes mosquitoes. A much smaller number of cases have been spread by sexual contact.

Most people have few or no symptoms if they get Zika virus. If symptoms occur, they are usually mild and last around 2 to 7 days. Serious complications and deaths from Zika virus are uncommon.

Zika virus infection during pregnancy can cause birth defects such as microcephaly (small head size) and problems with brain development. Research suggests that between 4% and 6% of infants born to mothers who have had a Zika virus infection during pregnancy have a birth defect.

Less commonly, Zika virus can cause neurological complications such as Guillain-Barré syndrome (GBS).

How the virus spreads

Zika virus is spread by the bite of an infected female Aedes mosquito, most commonly Aedes aegypti. The Aedes mosquito is not found in the UK; and there is currently no risk of the infection being spread within the UK.

Globally, cases of sexually transmitted Zika virus infection have been reported. Most cases have involved male-to-female spread but male-to-male and female-to-male transmission have also been reported as a very rare occurrence. There is also a potential risk of female- to-female transmission. Zika virus is not spread by social contact, including through kissing, hugging, or shaking hands.

Areas affected by Zika virus transmission

Transmission of Zika virus occurs in parts of Africa, Asia, the Pacific Islands, Central and South America and the Caribbean. Information on the risk of Zika virus is available from NaTHNaC Country Information pages (information is found in the ‘Other Risks’ section). As the risk of Zika virus can change in countries, this should be checked regularly.

Countries with current or past cases of Zika virus transmission have been given one of three ratings: risk, very low risk, or negligible risk (see Table 1). This rating is based on an assessment of the transmission of Zika virus in a country.

Table 1. Zika virus risk ratings

Risk Rating	Criteria
Risk	Evidence of current or recent outbreaks with significant transmission, new introduction or re-introduction of Zika virus, or endemic transmission.
Very low risk	Evidence of interrupted transmission but a potential for future transmission due to presence of Aedes mosquito in country.
Negligible risk	Countries or areas which had well managed localised clusters and have a potential for future localised transmission, but there are robust surveillance and outbreak control systems which will rapidly identify and contain outbreaks.

Travellers are at greatest risk of acquiring Zika virus infection when travelling in a risk country. The individual risk of infection may be lowered when mosquito bite avoidance measures are followed scrupulously.

Zika virus symptoms

After someone has been bitten by an infected mosquito, it can take between 3 and 12 days for symptoms to develop.

Most people will have no symptoms at all. Those that do develop symptoms will usually have a mild illness that lasts 2 to 7 days and starts between 3 to 12 days after being bitten by an infected mosquito. Typical symptoms include:

• rash
• generalised itching
• fever
• headache
• joint pain (sometimes with tissue swelling, around the ankles and other joints)
• muscle pain
• conjunctivitis/red eyes
• lower back pain
• pain behind the eyes

There is no difference between the symptoms seen in women who are pregnant and those that are not. The symptoms of Zika virus infection are similar to dengue (caused by a related virus) or chikungunya, illnesses which often occur in the same areas as Zika virus and are also transmitted by infected mosquitoes.

Complications of Zika virus infection

Although hospitalisations and deaths from Zika virus are not common, infection during pregnancy can cause serious complications as the virus can pass from an infected woman to their fetus.

Birth defects can occur whether the pregnant woman had symptoms of Zika virus or not; and are more likely if the infection occurred in the first or second trimester. Complications do not occur in every pregnancy. Approximately 5 – 15% of pregnant woman infected with Zika virus will experience a complication in pregnancy.

Complications include microcephaly (small head circumference) and problems with brain development, limb contractures, hearing and visual disturbances. Collectively this group of symptoms is called Congenital Zika Syndrome. Independently from this, Zika virus infection during pregnancy increases the risk of miscarriage and preterm birth.

Rarely, Zika virus is a trigger of neurological complications such as Guillain-Barré syndrome (GBS) which can cause muscle weakness and paralysis.

Treatment for Zika virus

There is no specific treatment for Zika virus infection. Symptoms are normally managed by rest, ensuring good fluid intake, and pain relief such as paracetamol when needed.

Vaccination for Zika virus

There is currently no vaccine to prevent Zika virus infection. Prevention is by minimising mosquito bites through being vigilant with mosquito bite precautions.

 Advice on prevention of sexual transmission of Zika virus

Advice for women and couples planning a pregnancy after travelling to an area with Zika transmission (Table 2)

To prevent infection spreading through sexual contact, and to prevent pregnancy related harms, additional sexual precautions are advised:

• On returning to the UK, women should avoid becoming pregnant for two months after the date of return if only the woman travelled
• On returning to the UK, women should avoid becoming pregnant for three months after the date of return if they travelled with their male partner or if their male partner travelled alone
• Use of effective contraception AND barrier methods (condoms) is advised during the above time periods

Advice for pregnant women planning travel

• You should discuss the suitability of travel and the potential risk that Zika virus may present to pregnancy with your health care provider
• You should avoid unprotected sex with anyone who has been to a country at risk of Zika virus transmission for the remainder of your pregnancy
• If travel cannot be avoided, you should use be vigilant with mosquito bite prevention

Advice for pregnant women returning from a country where there is risk of Zika with no symptoms ( Table 2)

• Zika virus testing is only recommended in certain circumstances. You do not need to be tested for Zika virus infection if:
  • You have no symptoms suggestive of Zika virus infection within two weeks of leaving a country where there is a risk of Zika virus infection
• You should inform your midwife of your travel
• You should avoid unprotected sex with anyone who has been to a country at risk of Zika virus transmission for the remainder of your pregnancy

Advice for pregnant women and couples returning from a risk country with symptoms (Table 2)

• The symptoms of Zika virus infection can be similar to other infections spread by mosquitoes including dengue, chikungunya and malaria; and can be similar to some infections seen in pregnancy that are not related to travel.
  
  Anyone who has recently returned from an area at risk of Zika and has a fever, rash or flu-like illness, should discuss with a healthcare professional without delay. The healthcare professional should be informed of recent overseas travel.

Table 2. Advice on prevention of sexual transmission of Zika virus

Country risk rating	Advice for pregnant women and their sexual partners	Advice for couples planning pregnancy prior to, during or within 6 months after travel
Risk	Consistent use of barrier methods (e.g. condoms) during and after travel is advised to reduce the risk of the developing fetus being exposed to Zika virus. Barrier methods should be continued for the duration of the pregnancy if the couple both travelled, or if just the male partner travelled. The couple should use barrier measures even in the absence of Zika symptoms	Consistent use of effective contraception and barrier methods (e.g. condoms) during and after travel is advised to reduce the risk of conception and the developing fetus being exposed to Zika virus. These measures should be used even in the absence of symptoms while travelling and if: - Both partners travelled, for 3 months after return or after last possible Zika virus exposure (note 1) - Male partner travelled only, for 3 months after return or after last possible Zika virus exposure(note 1) - Female partner travelled only, for 2 months after return or after last possible Zika virus exposure (note 1) These measures should be used while travelling and if: - Both partners travelled, for 3 months after return - Male traveller only, for 3 months after return - Female traveller only, for 2 months after return
Very low or negligible risk	No specific precautions required	No specific precautions required

Note 1: Last possible Zika virus exposure is defined as the date of leaving an area with Zika virus risk, or the date on which unprotected sexual contact with a potentially infectious partner took place.

Testing for Zika virus

The GP or midwife will ask questions about symptoms and travel history. They will advise whether further assessments are needed, including laboratory testing.

The GP or midwife will also discuss ultrasound scanning. Some women may also require referral to a fetal medicine unit.

Laboratory tests are recommended for all patients with suspected Zika virus infection, with current or previous symptoms. Precautionary testing is not recommended for people who have never had symptoms.

Advice for pregnant women who are diagnosed with Zika virus infection

Pregnant women who have a test that suggests a Zika virus infection will be referred to their local specialist fetal medicine unit and a consultant will advise on next steps such as the need for further scans.

If a problem is detected with their baby’s development, they may be offered a further test called ‘amniocentesis’. This procedure involves removing a small sample of amniotic fluid from the womb so the cells it contains can be tested. Before the woman has amniocentesis, a healthcare professional will explain the procedure, including why they think it is necessary and the benefits and risks of this test.

Potential risks to a baby from Zika virus infection

If someone has been diagnosed with a Zika virus infection during pregnancy, this does not necessarily mean the virus has affected the baby. They will be cared for and monitored throughout their pregnancy by the fetal medicine unit and their midwife, and kept informed by their healthcare team.

Treatment and follow-up

There is currently no specific treatment for Zika virus infection. Expert care and advice are available through the fetal medicine unit throughout pregnancy and beyond, via general practice surgeries, midwives and health visitors.

For further advice

Your GP surgery or midwife should be the first point of contact for anyone who has been to a Zika-affected country and needs advice. Further information can also be found at www.nhs.uk.

Travel health advice can be found at Travel Health Pro