Zika virus infection as a cause of congenital brain abnormalities and Guillain-Barré syndrome: From systematic review to living systematic review

Abstract

The Zika virus (ZIKV) outbreak in the Americas has caused Background. international concern due to neurological sequelae linked to the infection, such as microcephaly and Guillain-Barré syndrome (GBS). The World Health Organization stated that there is "sufficient evidence to conclude that Zika virus is a cause of congenital abnormalities and is a trigger of GBS". This conclusion was based on a systematic review of the evidence published until 30.05.2016. Since then, the body of evidence has grown substantially, leading to this update of that systematic review with new evidence published from 30.05.2016 -18.01.2017, update 1.We review evidence on the causal link between ZIKV infection and Methods. adverse congenital outcomes and the causal link between ZIKV infection and GBS or immune-mediated thrombocytopaenia purpura. We also describe the transition of the review into a living systematic review, a review that is continually updated.Between 30.05.2016 and 18.01.2017, we identified 2413 Results. publications, of which 101 publications were included. The evidence added in this update confirms the conclusion of a causal association between ZIKV and adverse congenital outcomes. New findings expand the evidence base in the dimensions of biological plausibility, strength of association, animal experiments and specificity. For GBS, the body of evidence has grown during the search period for update 1, but only for dimensions that were already populated in the previous version. There is still a limited understanding of the biological pathways that potentially cause the occurrence of autoimmune disease following ZIKV infection.This systematic review confirms previous conclusions that ZIKV Conclusions. is a cause of congenital abnormalities, including microcephaly, and is a trigger of GBS. The transition to living systematic review techniques and methodology provides a proof of concept for the use of these methods to synthesise evidence about an emerging pathogen such as ZIKV. Keywords

Impact of age-specific immunity on the timing and burden of the next Zika virus outbreak

“…ZIKV in an endemic setting, such as in Africa and Asia, could prove a suitable setting as well. However, ZIKV circulation in endemic setting is not well described and the occurrence of adverse outcomes in this context is less documented [9]. Further research in understanding the transmission of the virus in an endemic context is therefore needed.…”

“…In 2015, doctors in Brazil started reporting clusters of infants born with microcephaly, a severe congenital abnormality, and of adults with Guillain-Barré syndrome, a paralyzing neurological condition, resulting in the declaration by the World Health Organization (WHO) of a Public Health Emergency of International Concern (PHEIC) [7]. WHO stated, in September 2016, that ZIKV in pregnancy was the most likely cause of the clusters of microcephaly, and other adverse congenital outcomes [8,9]. The risk of an affected pregnancy appears highest during the first trimester, with estimates between 1.0 and 4.5% [10,11].…”

Emergence of evidence during disease outbreaks: lessons learnt from the Zika virus outbreak

“…During the period of the first review [10] and subsequent update [13], we screened 2,847 publications. During the remaining period, between January 7, 2017 and January 1, 2019, we screened an additional 2,594 publications.…”

Impact of age-specific immunity on the timing and burden of the next Zika virus outbreak

“…ZIKV in an endemic setting, such as in Africa and Asia, could prove a suitable setting as well. However, ZIKV circulation in endemic setting is not well described and the occurrence of adverse outcomes in this context is less documented Counotte et al (2018). Further research in understanding the transmission of the virus in an endemic context is therefore needed.…”

“…In 2015, doctors in Brazil started reporting clusters of infants born with microcephaly, a severe congenital abnormality, and of adults with Guillain-Barré syndrome, a paralyzing neurological condition, resulting in the declaration by the World Health Organization (WHO) of a Public Health Emergency of International Concern (PHEIC) (World Health Organization, 2016). WHO stated, in September 2016, that ZIKV in pregnancy was the most likely cause of the clusters of microcephaly, and other adverse congenital outcomes (Krauer et al, 2017; Counotte et al, 2018). The risk of an affected pregnancy appears highest during the first trimester, with estimates between 1.0 and 4.5% (Cauchemez et al, 2016; Johansson et al, 2016).…”