2016 Zika Linked Microcephaly In Brazil - Lancet ID

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Association between Zika virus infection and microcephaly in Brazil, January to May, 2016: preliminary report of a case-control study

http://www.thelancet.com/journals/laninf/article/PIIS1473-3099(16)30318-8/fulltext

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Dr Thalia Velho Barreto de Araújo, PhDPress enter key for correspondence informationPress enter key to Email the author

, 

Prof Laura Cunha Rodrigues, PhD

, 

Prof Ricardo Arraes de Alencar Ximenes, PhD

, 

Demócrito de Barros Miranda-Filho, PhD

, 

Ulisses Ramos Montarroyos, PhD

, 

Ana Paula Lopes de Melo, MSc

, 

Sandra Valongueiro, PhD

, 

Maria de Fátima Pessoa Militão de Albuquerque, PhD

, 

Wayner Vieira Souza, PhD

, 

Cynthia Braga, PhD

,

Sinval Pinto Brandão Filho, PhD

, 

Marli Tenório Cordeiro, PhD

, 

Enrique Vazquez, PhD

, 

Danielle Di Cavalcanti Souza Cruz, MD

, 

Cláudio Maierovitch Pessanha Henriques, MSc

, 

Luciana Caroline Albuquerque Bezerra, MSc

, 

Priscila Mayrelle da Silva Castanha, PhD

, 

Rafael Dhalia, PhD

, 

Ernesto Torres Azevedo Marques-Júnior, PhD

, 

Prof Celina Maria Turchi Martelli, PhD

 on behalf of investigators from the Microcephaly Epidemic Research Group the Brazilian Ministry of Health the Pan American Health Organization Instituto de Medicina Integral Professor Fernando Figueirathe State Health Department of Pernambuco^†

^†Investigators contributing on behalf of these organisations are listed at the end of the report

 

Contributors

TVBA, CMTM, LCR, RAAX, and DBM-F participated in all phases of the study. All other authors participated in data interpretation and critical revision of the manuscript. All authors approved the final version and agree to be accountable for all aspects of the work.

Declaration of interests

We declare no competing interests.

Contributing investigators

Microcephaly Epidemic Research Group: Sergio Souza da Cunha, Carmen Dhalia, Marcela Santos, Fanny Cortes, Marcus K Eder

Brazilian Ministry of Health: Wanderson Kleber de Oliveira, Giovanini Evelim Coelho

Pan American Health Organization: Juan Jose Cortez-Escalante, Carlos Frederico Campelo de Albuquerque de Melo, Pilar Ramón-Pardo, Sylvain Aldighieri, Jairo Méndez-Rico, Marcos Espinal

Instituto de Medicina Integral Professor Fernando Figueira: Leuridan Torres, Adriano Nassri Hazin, Ana Van der Linden, Mônica Coentro

State Health Department of Pernambuco: George Santiago Dimech, Romildo Siqueira de Assunção, Patricia Ismael de Carvalho, Valdete Felix Oliveira

For further details please see the appendix.

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Background

The microcephaly epidemic, which started in Brazil in 2015, was declared a Public Health Emergency of International Concern by WHO in 2016. We report the preliminary results of a case-control study investigating the association between microcephaly and Zika virus infection during pregnancy.

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Methods

We did this case-control study in eight public hospitals in Recife, Brazil. Cases were neonates with microcephaly. Two controls (neonates without microcephaly), matched by expected date of delivery and area of residence, were selected for each case. Serum samples of cases and controls and cerebrospinal fluid samples of cases were tested for Zika virus-specific IgM and by quantitative RT-PCR. Laboratory-confirmed Zika virus infection during pregnancy was defined as detection of Zika virus-specific IgM or a positive RT-PCR result in neonates. Maternal serum samples were tested by plaque reduction neutralisation assay for Zika virus and dengue virus. We estimated crude odds ratios (ORs) and 95% CIs using a median unbiased estimator for binary data in an unconditional logistic regression model. We estimated ORs separately for cases with and without radiological evidence of brain abnormalities.

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Findings

Between Jan 15, 2016, and May 2, 2016, we prospectively recruited 32 cases and 62 controls. 24 (80%) of 30 mothers of cases had Zika virus infection compared with 39 (64%) of 61 mothers of controls (p=0·12). 13 (41%) of 32 cases and none of 62 controls had laboratory-confirmed Zika virus infection; crude overall OR 55·5 (95% CI 8·6–∞); OR 113·3 (95% CI 14·5–∞) for seven cases with brain abnormalities; and OR 24·7 (95% CI 2·9–∞) for four cases without brain abnormalities.

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Interpretation

Our data suggest that the microcephaly epidemic is a result of congenital Zika virus infection. We await further data from this ongoing study to assess other potential risk factors and to confirm the strength of association in a larger sample size.