Marco Cáceres di Iorio

Jumping the Gun on the Zika-Microcephaly Connection

On  January 21, 2016, TIME magazine published an article titled “The Brazilian Birth-Defect Rate Is Soaring Dramatically, Possibly Due to the Zika Virus. The article, written by Nash Jenkins, opens with the following paragraph:

Brazilian authorities have reported a huge increase in the number of babies born in the country with uncommonly small heads, and suspect that the surge is linked to an outbreak of the mosquito-borne Zika virus.1

Note the words “suspect” and “linked.”

TIME published another article on January 21 titled “U.S. Launches ‘Full-court Press’ for a Zika Vaccine,” written by Alexandra Sifferlin. The opening paragraph of that piece reads:

The United States is pushing to develop a vaccine for the Zika virus, a top health official said Thursday, as doctors warn that the mosquito-borne disease, which causes birth defects in infants and is typically found abroad, has become a growing threat in the U.S.2

Now, note the phrase “which causes birth defects in infants.”

In the first article, the message conveyed is that it is unclear whether the Zika virus is the actual cause of the current epidemic of babies being born with shrunken heads and brain damage—a condition known as microcephaly. According to the Jenkins piece, Brazilian authorities suspect that the epidemic is linked to the virus.

This uncertainty is consistent with the position of the Centers for Disease Control and Prevention (CDC) regarding the Brazilian microcephaly epidemic and Zika. The CDC states on its website:

…. additional studies are needed to further characterize this relationship. More studies are planned to learn more about the risks of Zika virus infection during pregnancy.3

So the message from the CDC is that we still do not know whether Zika equals microcephaly in Brazilian babies. The agency confirms that “additional studies are needed.” Echoing that uncertainty, in a recent article in The New England Journal of Medicine, Anthony Fauci, MD and David Morens, MD of the U.S. National Institute of Allergy and Infectious Diseases pointed out that there is a “lack of definitive proof of any causal relationship” between Zika and the microcephaly cases in Brazil.4

Scientists from the CDC have determined that placenta samples taken from two Brazilian women who had carried fetuses found to have microcephaly tested positive for Zika, and that their newborn babies, who ultimately died, showed evidence of the virus in their brains. Lyle Petersen, MD, MPH, who is the director of the CDC’s division of vector-borne diseases, believes this information offers the “strongest evidence to date of a possible link between Zika virus and microcephaly and other congenital abnormalities.”5

But Dr. Petersen stopped short of declaring a causal relationship. He said, “I wouldn’t use [the term] smoking gun…”5  Why did he say that? Because, as we all know, correlation does not equal causation.

Some members of the U.S. media seem less inclined to show such restraint. This is certainly the case with Ms. Sifferlin, who is more than glad to point to Zika as the smoking gun, and thereby fuel the process of irresponsibly transforming what is still just a theory into something else.

Soon, other reporters, editorial writers and news commentators may be tempted to follow suit and treat the Zika-microcephaly connection as a scientific fact, a done deal.Fear sells and the media manipulating public opinion can interfere with a proper investigation by government health officials and scientists to the point where they’ll feel growing pressure to prematurely come to conclusions and take action before asking all the right questions that need to be answered about this tragic and evolving epidemic of microcephaly.

It’s called “Groupthink”—“a psychological phenomenon that occurs within a group of people, in which the desire for harmony or conformity in the group results in an irrational or dysfunctional decision-making outcome.”6

Should this happen, it leaves open the possibility of misdiagnosing the problem andmisdirecting the public health policy response. The recommended “cure”—be it rushing to develop a new vaccine or ordering mass anti-mosquito fumigation campaigns using toxic pesticides—may end up making matters even worse.

Medical history is filled with examples of hastily prescribed “cures” gone wrong.


1 Jenkins N. The Brazilian Birth-Defect Rate Is Soaring Dramatically, Possibly Due to the Zika Virus. TIME Jan. 21, 2016.
2 Sifferlin A. U.S. Launches ‘Full-court Press’ for a Zika Vaccine. TIME Jan. 21, 2016.
3 Centers for Disease Control and Prevention (CDC). Question and Answers: Zika virus infection (Zika) and pregnancy.
4 Fauci A, Morens D. Zika Virus in the Americas—Yet Another Arbovirus Threat. The New England Journal of Medicine Jan. 13, 2016.
5 Branswell H. Zika virus likely tied to Brazil’s surge in babies born with small heads, CDC says. STAT Jan. 13, 2016.
6 Wikipedia. Groupthink.

2 Responses to “Jumping the Gun on the Zika-Microcephaly Connection”

  1. I. Demei

    What i would like to know is if there is a link between the mandatory dtap vaccination campaign of 2015 for pregnant women in brazil and the spectacular rise of microcephaly cases now linked/blamed on the zika virus…..



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