Children with dengue fever may be protected against symptomatic Zika

Dengue fever is endemic in the Americas. Zika was only reported in this region in 2015. The viruses are very similar: they are transmitted by Aedes aegypti mosquitoes and can cause similar symptoms, including fever, rashes and joint and muscle pain.

People working on mosquito-borne diseases think that there is an immunological interaction between dengue and Zika.

A new study by scientists from Michigan and California suggests that an earlier infection with the dengue virus could protect children from symptomatic infection with the Zika virus. These results support the idea that previous dengue infection may provide cross-protection against symptomatic Zika.

The lead author of the study, Aubree Gordon, said, "We do not believe that dengue immunity protects against infection (by the Zika virus), or at least that does not seem to be the case. in our study. However, in children infected with Zika virus, previous exposure to dengue protected them from symptomatic Zika virus disease. "

For their study, scientists gathered data from their long-standing dengue cohort study established in 2004 in Managua.

Of the approximately 3,700 participants (children aged 2 to 14 years), 3,027 had a history of dengue infection, of which 743 had at least one previous dengue infection and 176 with recent dengue infection . Using tests, the researchers found that 1,356 of them had Zika infection and 560 of them had symptomatic Zika.

The scientists then compared children with previous dengue infection to those who did not know whether prior dengue infection had an impact on Zika virus infection and on the severity of the infection.

Scientists found that children with previous dengue infection were 38% less likely to develop symptomatic zika than children without previous dengue exposure.

Eva Harris, co-author of the study, said: "Researchers are paying particular attention to a phenomenon called antibody-dependent improvement. In some cases, people who have already had a dengue infection develop antibodies that, instead of protecting their hosts, prevent them from fighting, but strengthening, a subsequent infection. "

"However, in the current study, we have not examined the serious consequences of Zika. We badyzed uncomplicated Zika in our pediatric population and found that an earlier dengue infection was effectively protected against the disease. This is consistent with our previous studies on the role of dengue antibodies in the treatment of uncomplicated dengue fever. "

Gordon said, "If there are interactions if it protects you from dengue, that's great. Or if it helps you not to be symptomatic, that's fine. But there is still concern that antibodies protect up to a certain point, and as soon as they reach a certain level, they now constitute a risk of serious illness. And so I think that needs to be looked at very closely. "

The study, published in PLOS Medicine, was funded by grants R01 AI099631 (AB), P01 AI106695 (EH) and U19 AI118610 (EH) of the National Institute of Allergy and Infectious Diseases. National Institutes of Health, as well as the VE-1 Grant (EH) of the Bill & Melinda Gates Pediatric Dengue Vaccine Initiative.