Let’s take a step back

World Health Organisation (WHO) officials are confident that the association between Zika virus and microcephaly could be confirmed within weeks. During a press conference on Friday 12th Feb, Marie-Paule Kieny, WHO’s assistant director-general for health systems and innovation told reporters that “it seems indeed that the link with Zika is becoming more and more probable, so I think that we need a few more weeks and a few more studies to have this straight”.

The World Health Organization declared on the 1st of February an international public health emergency on Zika outbreak and observed increase in neurological disorders and neonatal malformations. So, it was not Zika itself, but rather the suspected link between the virus and microcephaly, what prompetd the international public health emergency declaration.

However, the latest report released by the Brazilian health authorities on the link between the virus and confirmed microcephaly cases raises more questions than answers. Of the 5.079 suspected cases of microcephaly reported in the country since Oct 2015, only 462 have been confirmed, and only 41 of the confirmed cases are related to Zika. Most of the confirmed cases are concetrated in the impoverished northeast.

We might or might not get more certainty in the next two weeks, but some epidemiologists are pointing to other potential factors that could explain the microcephaly outbreak in Brazil, including under-reporting over the last five years, exposure to agrochemicals, malnutrition, environmental degradation or poverty-related causes.

One cannot rush scientific evidence, and today we still have more questions than answers. Should WHO have waited to have a stronger evidence of the link between Zika and microcephaly before declaring the international public health emergency? To be fair, the organization has done until now a good job in communicating what they know and don’t know about the connection between both. Let’s see what the following weeks bring us in terms of scientific evidence and communication of findings, and let’s not overlook other possible causes.