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Researchers discover that previous exposure to dengue fever protects Zika's children
Previous dengue infection may protect children from symptomatic infection with Zika virus.
A study by an international group of researchers, including those from the University of Michigan and the University of California at Berkeley, came to this conclusion.
"We do not think this immunity against dengue protects from infection (with Zika), 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 fever protected them from Zika's symptomatic disease, "said lead author Aubree Gordon, badistant professor of epidemiology at the School. public health UM.
Children who had already contracted dengue were 38% less likely to develop symptomatic Zika than children without prior dengue exposure
Gordon and his UC Berkeley collaborators, the Institute of the Ministry of Health and Sustainable Sciences of Nicaragua in Managua, used data from their long-term cohort study on pediatric dengue, 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 researchers compared children who had previously had a dengue infection to those who had not experienced it to determine whether prior dengue infection had an impact on Zika virus infection. on the severity of the infection.
The researchers found that among children infected with the Zika virus, children with previous dengue infection were 38% less likely to develop symptomatic Zika than children without previous dengue exposure.
While dengue fever is endemic in the Americas, Zika has not been reported in the region before 2015. The viruses are very similar: they are transmitted by Aedes aegypti mosquitoes and can cause similar symptoms, including fever, rashes and muscle and joint pain. .
Those working on mosquito-borne diseases believe that there is an immunological interaction between dengue and Zika, said study co-author Eva Harris of UC-Berkeley.
The researchers pay special attention to a phenomenon called "antibody-dependent enhancement," said Harris. In some cases, people who have already had a dengue infection develop antibodies that, instead of protecting their hosts, prevent them from fighting, but strengthen, a subsequent infection.
The Harris international team has recently shown that this was the case in children in the Nicaraguan cohort study. The researchers believe that this mechanism could be at the origin of the serious cases of Zika having caused neurological problems.
"However, in this study, we have not examined the serious consequences of Zika," Harris said. "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 relation to the uncomplicated dengue disease.
Gordon said that additional research is needed to examine the interaction.
"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, she says. "But there is always the concern that antibodies protect up to a certain point and, once 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. "
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