The WHO Secretariat briefed the Committee on action in implementing the Temporary Recommendations issued by the Director-General on 1 February 2016, and on clusters of microcephaly and Guillain-Barré Syndrome (GBS) that have had a temporal association with Zika virus transmission. The Committee was provided with additional data from observational, comparative and experimental studies on the possible causal association between Zika virus infection, microcephaly and GBS.
The following States Parties provided information on microcephaly, GBS and other neurological disorders occurring in the presence of Zika virus transmission: Brazil, Cabo Verde, Colombia, France, and the United States of America.
The Committee noted the new information from States Parties and academic institutions in terms of case reports, case series, 1 case control study (GBS) and 1 cohort study (microcephaly) on congenital abnormalities and neurologic disease in the presence of Zika virus infection. It reinforced the need for further work to generate additional evidence on this association and to understand any inconsistencies in data from countries. The Committee advised that the clusters of microcephaly cases and other neurological disorders continue to constitute a Public Health Emergency of International Concern (PHEIC), and that there is increasing evidence that there is a causal relationship with Zika virus.
The Committee provided the following advice to the Director-General for her consideration to address the PHEIC, in accordance with IHR (2005).
Microcephaly, other neurological disorders and Zika virus
- Research into the relationship between new clusters of microcephaly, other neurological disorders, including GBS, and Zika virus, should be intensified.
- Particular attention should be given to generating additional data on the genetic sequences and clinical effect of different Zika virus strains, studying the neuropathology of microcephaly, conducting additional case-control and cohort studies in other and more recently infected settings, and developing animal models for experimental studies.
- Research on the natural history of Zika virus infection should be expedited, including on the rates of asymptomatic infection, the implications of asymptomatic infection, particularly with respect to pregnancy, and the persistence of virus excretion.
- Retrospective and prospective studies of the rates of microcephaly and other neurological disorders should be conducted in other areas known to have had Zika virus transmission but where such clusters were not observed.
- Research should continue to explore the possibility of other causative factors or co-factors for the observed clusters of microcephaly and other neurological disorders.
- To facilitate this research and ensure the most rapid results:
- surveillance for microcephaly and GBS should be standardized and enhanced, particularly in areas of known Zika virus transmission and areas at risk,
- work should begin on the development of a potential case definition for ‘congenital Zika infection’,
- clinical, virologic and epidemiologic data related to the increased rates of microcephaly and/or GBS, and Zika virus transmission, should be rapidly shared with the World Health Organization to facilitate international understanding of the these events, to guide international support for control efforts, and to prioritize further research and product development.
Surveillance
- Surveillance for and notification of Zika virus infection should be enhanced with the dissemination of standard case definitions and diagnostics to areas of transmission and at-risk areas; newly infected areas should undertake the vector control measures outlined below.
Vector control
- Vector surveillance, including the determination of mosquito vector species and their sensitivity to insecticides, should be enhanced to strengthen risk assessments and vector control measures.
- Vector control measures and appropriate personal protective measures should be aggressively promoted and implemented to reduce the risk of exposure to Zika virus.
- Countries should strengthen vector control measures in the long term and the Director-General of WHO should explore the use of IHR mechanisms, and consider bringing this to a forthcoming World Health Assembly, as means to better engage countries on this issue.
Risk communication
- Risk communication should be enhanced in countries with Zika virus transmission to address population concerns, enhance community engagement, improve reporting, and ensure application of vector control and personal protective measures.
- These measures should be based on an appropriate assessment of public perception, knowledge and information; the impact of risk communication measures should be rigorously evaluated to guide their adaptation and improve their impact.
- Attention should be given to ensuring women of childbearing age and particularly pregnant women have the necessary information and materials to reduce risk of exposure.
- Information on the risk of sexual transmission, and measures to reduce that risk, should be available to people living in and returning from areas of reported Zika virus transmission.
Clinical care
- Pregnant women who have been exposed to Zika virus should be counselled and followed for birth outcomes based on the best available information and national practice and policies,
- In areas of known Zika virus transmission, health services should be prepared for potential increases in neurological syndromes and/or congenital malformations.
Travel measures
- There should be no general restrictions on travel or trade with countries, areas and/or territories with Zika virus transmission.
- Pregnant women should be advised not travel to areas of ongoing Zika virus outbreaks; pregnant women whose sexual partners live in or travel to areas with Zika virus outbreaks should ensure safe sexual practices or abstain from sex for the duration of their pregnancy.
- Travellers to areas with Zika virus outbreaks should be provided with up to date advice on potential risks and appropriate measures to reduce the possibility of exposure to mosquito bites and, upon return, should take appropriate measures, including safe sex, to reduce the risk of onward transmission.
- The World Health Organization should regularly update its guidance on travel with evolving information on the nature and duration of risks associated with Zika virus infection.
- Standard WHO recommendations regarding vector control at airports should be implemented in keeping with the IHR (2005). Countries should consider the disinsection of aircraft.
Research & product development
- The development of new diagnostics for Zika virus infection should be prioritized to facilitate surveillance and control measures, and especially the management of pregnancy.
- Research, development and evaluation of novel vector control measures should be pursued with particular urgency.
- Research and development efforts should also be intensified for Zika virus vaccines and therapeutics in the medium term.
Based on this advice the Director-General declared the continuation of the Public Health Emergency of International Concern (PHEIC). The Director-General endorsed the Committee’s advice and issued them as Temporary Recommendations under IHR (2005). The Director-General thanked the Committee Members and Advisors for their advice.
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Source: WHO
