Evidence of Cross-Reactivity Between Zika and Dengue Virus

A cross-sectional analysis of data collected over 3 summers in Rio Grande do Norte (RN), Brazil (January-March 2015, 2016, and 2017), provides epidemiological evidence that preexisting Dengue virus antibodies have cross-reactivity with Zika, according to a presentation given by Brazilian researchers at ID Week 2018 . This finding is based on prevalence data, which showed the following:

• Suspected Dengue fever cases: 6902, 34,642, and 1,677 cases during the summers of 2015, 2016, and 2017, respectively.
• Confirmed Dengue fever cases: 523, 7,599, and 204 cases during the summers of 2015, 2016, and 2017, respectively.
• Suspected Zika cases:  3,486 and 86 cases during summers of 2016 and 2017, respectively.
• Confirmed Zika cases: 97 and 0 cases during summers of 2016 and 2017, respectively.
• Total Zika cases during 2015 and 2016: 14,584 (represents <0.5% of RN population).

The researchers concluded that these data suggest the following:

• Dengue fever outbreak in 2016 contributed to decrease of 97.53% in the prevalence of Zika virus infection in 2017, suggesting preexisting Dengue virus antibodies partially neutralize Zika virus infection through serologic cross-reactivity.
• Findings suggest that Dengue virus vaccines might offer some protection against Zika virus but further studies are needed.

Reference

Neto NNM, Maia J, Zacarkim MR, et al. Cross-Reactivity Between Zika and Dengue Virus: A Cross-Sectional Analysis in Rio Grande do Norte, Brazil. Presented at: 2018 ID Week; October 3-7, 2018; San Francisco, California. Abstract 445.