Pregnancy outcomes in mothers with a history of travel to a country with active Zika transmission

Key points

• Zika virus (ZIKV) is an emerging viral infection with increasing transmission in South and Central America and the Caribbean over the past few months.
• Even though not yet scientifically proven, a causal relationship between ZIKV infection in pregnancy and microcephaly is strongly suspected.
• This study will describe the risk of an adverse pregnancy outcome related to infection with ZIKV during pregnancy.

Surveillance Period

March 2016 – February 2017

Background

Since early 2015 when Zika virus (ZIKV) infection was first reported in Brazil, ZIVK has rapidly spread over most countries in South and Central America, the Caribbean and countries outside this region. An unusually high number of babies born with microcephaly were reported in Brazil, six months after the rapid increase of cases of ZIKV infection, concentrated particularly in those areas with high rates of the disease. The high numbers of cases are likely to be an overestimate due to case ascertainment; however they are considerable and thus were declared as Public Health Emergency of International Concern by the WHO in February 2016. Even though not yet scientifically proven, a causal relationship between ZIKV infection in pregnancy and microcephaly is strongly suspected. Two babies with microcephaly and confirmed ZIKV infection of mothers resident in countries without active ZIKV but who had travelled to Brazil during their pregnancy have been reported to date^[1].

Almost 1.4 million UK residents travelled to South and Central America and the Caribbean on average each year between 2010 and 2014, 25% of those are women of child bearing age^[2].

This study will carry out national surveillance in the UK, to assess the risk of having an adverse pregnancy outcome after travel to a country with active Zika transmission

Objective

To use the UK Obstetric Surveillance System to describe the risk of congenital abnormalities in pregnant women with a history of travel to a country with active ZIKV transmission

Research questions

• What is the risk of fetal congenital abnormalities associated with travel to a country with active ZIKV transmission?
• What is the number of cases of fetal congenital abnormalities associated with travel to a country with active ZIKV transmission in the UK over a period of 12 months?
• What are the typical features of this condition?
• How does it present in relation to time of infection during pregnancy?
• Are there any other adverse pregnancy outcomes associated with travel to a country with active ZIKV transmission?

Case definition

Two case definitions will be added to the reporting card

1. Any pregnant woman with a history of travel to a country with active ZIKV transmission during pregnancy or 4 weeks before conception and no adverse pregnancy outcome.
2. Any pregnant woman with a history of travel to a country with active ZIKV transmission during pregnancy or 4 weeks before conception where a fetal abnormality has been detected or miscarriage, stillbirth, neonatal death or termination of pregnancy occurred.

Reporters are requested to report the numbers of women in their unit who fall into either category. Detailed data will only be requested on women with an adverse pregnancy outcome at this stage i.e. UKOSS will only collect numbers of women falling into group 1; reporting clinicians will not be requested to complete a data collection form. Data collection forms will be sent for completion of further details about women in group 2.

To confirm if the country visited has had active ZIKV transmission in the past nine months please use this link: http://ecdc.europa.eu/en/healthtopics/zika_virus_infection/zika-outbreak/Pages/Zika-transmission-past-9-months.aspx

Funding

Public Health England

Ethics approval

UKOSS has been approved by the North London REC1 (REC Ref. Number: 10/H0717/20).

Sample Data Collection Form (DCF)

UKOSS Zika Virus Data Collection Form