Fear surrounding the threat of Zika virus has plagued the media, and its steady spread across Latin America and Pacific island nations — along with its inevitable arrival in parts of the continental U.S. — has many worried. The mysterious virus, suspected of causing birth defects, has provoked the U.S. Centers for Disease Control and Prevention to update its recommendations on pregnancy and sex. But there are plenty of skeptics wondering what we should and shouldn’t believe. Now, there seems to be a breakthrough.

Amidst the growing concerns, health officials in Brazil have admitted that Zika alone may not be responsible for the rise in birth defects in parts of the country.

The virus may be linked to the birth defect called microcephaly, but while Zika has been spreading at extremely high rates throughout Brazil, microcephaly has not.

“We suspect that something more than Zika virus is causing the high intensity and severity of cases,” explains Dr. Fatima Marinho, Director of Information and Health Analysis at Brazil’s Ministry of Health.

Here are some facts you should know:

Almost All Cases Of Brazil Microcephaly Took Place In The Northeast

Since last November, Brazil has seen more than 1,700 cases of microcephaly or other birth defects of the central nervous system. When the cases were first detected, health officials believed they’d witness “an explosion of birth defects” across the country, but that wasn’t the case. In fact, data compiled by Marinho and colleagues found that socio-economic factors may be involved, since the majority of the women who gave birth to babies with microcephaly were poor and resided in small cities or on the outskirts of big cities. The outbreak also occurred in extremely poverty-stricken areas of Brazil that use massive amount of banned pesticides. Environmental pollution and toxic pesticide exposure have been linked to many adverse health effects, including birth defects.

There Is Not Enough Data

Not enough data can rightfully link the Zika virus to microcephaly, and the data that does exist mainly comes from incomplete hospital reports, with tests to confirm the virus often not carried out.

It’s even been suggested that microcephaly may be the combination of Zika along with other infections such as dengue and chikungunya, with the Brazilian doctor who first reportedly established the link between Zika virus and microcephaly now claiming Bovine viral diarrhea virus (BVDV) may be involved.

Colombian Women and Zika Virus

The New England Complex Systems Institute (NECSI) followed nearly 12,000 pregnant Colombian women infected with Zika virus and found no cases of microcephaly, yet four cases of microcephaly were reported among women who had Zika infection with no symptoms and were therefore not included in the study.

According to NECSI:

This gives a consistent interpretation that there is no direct link between Zika and microcephaly except for random co-occurrence. We note that the base rate of microcephaly in the absence of Zika is 140 per year in Colombia, which is consistent with the approximately 50 microcephaly cases in the first 4 months of 2016, only 4 of which have been connected to Zika. When interpreting Zika as the cause, background cases must be subtracted.

WHO Expert Weighs In

According to Florence Fouque, a World Health Organization (WHO) expert on animals that carry viruses, the public response to the Zika virus is “completely hysterical.” She said the hysteria comes from the findings of the virus harming pregnant women, and that it can be sexually transmitted.

“It’s like AIDS,” she said. “People make this link and that’s why they are really afraid.”

Oliver Brady, an epidemiologist with the London School of Hygiene and Tropical Medicine who was asked by Brazilian officials to assess the Zika-microcephaly situation, also weighed in on the subject:

You see that with a lot of arboviruses [viruses spread by mosquitoes and other insects]. . . They have pathogenic qualities and if you put them in the right tissue then they will cause some sort of damage. And they tend to be quite transmissible across a variety of barriers anyway. So it doesn’t necessarily mean that that’s the mechanism that’s happening out there in the field, even if it does work in the lab.

The U.S. Is Ignoring Valuable Data

Among those jumping to conclusions is the U.S., which, despite the data, has rushed to launch a clinical trial of an experimental Zika vaccine without conclusive proof that Zika causes microcephaly.

The trial will involve 80 healthy volunteers between the ages of 18 and 35. These participants will be vaccinated with varying doses of the experimental vaccine, and placebos will be given.

There are concerns about such a vaccine, Dr. Scott B. Halstead, former senior adviser of the Dengue Vaccine Initiative and the founder of Children’s Vaccine Initiative, told the University of Minnesota Center for Infectious Disease Research and Policy:

It’s happened. We have a vaccine that enhances dengue. . . . It’s clear as the nose on my face: Vaccine recipients less than 5 years old had five to seven times more rates of hospitalizations for severe dengue virus than placebo controls.

Halstead is specifically referring to a three-year study that suggested the vaccine causes antibody-dependent enhancement (ADE). He said: “Over time, you make and keep protective levels of antibody from the initial infection, but you lose the cross-reactive antibodies. . . . That allows a second dengue infection to cause severe illness.”

The University of Minnesota Center for Infectious Disease Research and Policy sided with concerns discussed by Dr. Philip K. Russell, the former director of the Walter Reed Army Institute of Research and commander of the U.S. Army Medical Research and Development Command, as well as founding president and chairman of the Sabin Vaccine Institute: “Russell said that the fact that Zika is occurring in areas where dengue has been endemic hints at a serious potential problem with ADE and Zika vaccine development.” Russell himself noted, “The current epidemic of Zika, which is usually mild disease, is made a lot worse in these populations,” and “I think there’s a major effect, but the studies haven’t been done yet to sort that out.”

Toxic Exposures For Battling Zika

Due to the media frenzy, many areas have increased their pesticide use as a means for combating the Zika virus. And while a Clean Water Act permit is typically required to spray pesticides in areas where they might end up in water, the Zika virus has been used as an excuse to further harm the planet and its inhabitants.

The Zika Vector Control Act was passed by the House of Representatives, exempting pesticide applicators from needing a Clean Water Act permit, even when spraying near water. But opponents say the bill has nothing to do with battling Zika, claiming it has been on the table for years, with the majority fighting to slap any name on it to make it convenient to the time.

Research has shown the detriments to such spraying, like the evidence presented at the Pediatric Academic Societies 2016 Meeting, which explained that aerial pesticide exposure is linked to an increased risk of developmental delays and autism spectrum disorder among children.

Mosquito Experts Know The Truth

Even mosquito experts suggest things aren’t right. According to Chris Barker, Ph.D., a researcher of mosquito-borne viruses at the University of California, Davis School of Veterinary Medicine:

“I think the risk for Zika actually setting up transmission cycles that become established in the continental U.S. is near zero.”

He anticipates the virus to mimic other tropical diseases spread by mosquitoes, like dengue fever and chikungunya, by making its way into the U.S. with small clusters of outbreaks in Southern states and not much activity elsewhere.