RIO DE JANEIRO – Often drowned out by the dire warnings and fear surrounding Zika, some medical professionals are saying that Brazil and international health officials have prematurely declared a link between the virus and what appears to be a surge in birth defects.
A few even argue that the Brazilian government is being irresponsible, given that a connection hasn’t been scientifically proven between the mosquito-borne virus and the birth defect known as microcephaly, which causes infants to be born with abnormally small heads.
“It’s a global scandal. Brazil has created a worldwide panic,” said Alexandre Dias Porto Chiavegatto Filho, a professor of epidemiology at the University of Sao Paulo, one of the most-respected universities in Latin America. “I’m not saying that Zika is not causing microcephaly, but I am saying that the ministry has yet to present any scientifically credible evidence to support that conclusion.”
Chiavegatto and others argue there are still too many unanswered questions to blame Zika. Why are the vast majority of the cases of microcephaly being reported in Brazil? Why haven’t they also shown up in proportional numbers in other countries hit hard by Zika, such as Colombia? (The answer, some say, is that Brazil was hit by Zika first, and microcephaly cases might be expected to crest elsewhere in the months ahead.)
And how can conclusions be drawn from government statistics that are flawed and possibly vastly underreported in the past, before Brazilian officials required doctors to report microcephaly cases?
In an article published Wednesday by the Annals of Internal Medicine, 14 Brazilian and American researchers said the link between Zika and microcephaly “remains presumptive.” The strongest evidence is circumstantial, they said, and there are challenges in confirming the connection.
But Brazilian Health Minister Marcelo Castro recently said he was “absolutely sure” of a causal link between Zika and microcephaly. He and other scientific experts around the world have pointed to studies that detected the presence of Zika in the brains of dead fetuses and in the placentas of babies diagnosed with microcephaly in the womb.
Note: Castro is basing his argument on a logical fallacy and not on scientific evidence. In logic, correlation does not imply causality.
If rain, for example, falls whenever I cross the main square in Larisa to get to the court, it does not mean I cause the rain to fall by walking across the main square. The rain was caused by many other factors that have nothing to do with me such as evaporation, transpiration, weather fronts and water cycles etc.
If Zika virus is found in the brains of dead fetuses diagnosed with microcephaly in the womb, it does not mean the Zika virus caused the microcephaly.
Microcephaly has been a long term problem, and is caused by other factors such malnutrition and vaccines according to the Mattos study.