The proportion of asymptomatic infections and spectrum of disease among pregnant women infected by Zika virus: systematic monitoring in French Guiana, 2016

Claude Flamand (1) , Camille Fritzell (1) , Severine Matheus (2) , Maryvonne Dueymes (3) , Gabriel Carles (4) , Anne Favre (3) , Antoine Enfissi (2) , Antoine Adde (1) , Magalie Pierre Demar (3) , Mirdad Kazanji (1) , Simon Cauchemez (5, 6) , Dominique Rousset (2)

1 Unité d'Epidémiologie [Cayenne, Guyane française]
2 CNR - laboratoire associé - Centre National de Référence pour les Arbovirus - Laboratoire de Virologie [Cayenne, Guyane française]
3 Centre Hospitalier Andrée Rosemon [Cayenne, Guyane Française]
4 Centre Hospitalier de l'Ouest Guyanais Franck Joly [Saint-Laurent-du-Maroni, Guyane Française]
5 Modélisation mathématique des maladies infectieuses
6 C3BI - Centre de Bioinformatique, Biostatistique et Biologie Intégrative

Zika virus (ZIKV) infection has been associated with complications during pregnancy. Although the presence of symptoms might be a risk factor for complication, the proportion of ZIKV-infected pregnant women with symptoms remains unknown. Following the emergence of ZIKV in French Guiana, all pregnancies in the territory were monitored by RT-PCR and/or detection of ZIKV antibodies. Follow-up data collected during pregnancy monitoring interviews were analysed from 1 February to 1 June 2016. We enrolled 3,050 pregnant women aged 14-48 years and 573 (19%) had laboratory-confirmed ZIKV infection. Rash, arthralgia, myalgia and conjunctival hyperaemia were more frequently observed in ZIKV-positive women; 23% of them (95% confidence interval (CI): 20-27) had at least one symptom compatible with ZIKV infection. Women 30 years and older were significantly more likely to have symptoms than younger women (28% vs 20%). The proportion of symptomatic infections varied from 17% in the remote interior to 35% in the urbanised population near the coast (adjusted risk ratio: 1.6; 95% CI: 1.4-1.9.). These estimates put findings on cohorts of symptomatic ZIKV-positive pregnant women into the wider context of an epidemic with mainly asymptomatic infections. The proportion of symptomatic ZIKV infections appears to vary substantially between populations.

Mots clés: French Guiana; Zika virus; epidemiology; outbreak; pregnant women

Domaines: Santé publique et épidémiologie; Maladies infectieuses; Maladies émergentes

Claude Flamand, Camille Fritzell, Severine Matheus, Maryvonne Dueymes, Gabriel Carles, et al.. The proportion of asymptomatic infections and spectrum of disease among pregnant women infected by Zika virus: systematic monitoring in French Guiana, 2016. Eurosurveillance, 2017, 22 (44), pp.17‑00102. ⟨10.2807/1560-7917.ES.2017.22.44.17-00102⟩. ⟨hal-02539219⟩