SBT Truth Check: AMA, Media wrong on “High Risk” of  Zika, Microcephaly and CDC Warning.

The AMA, ABC News and other sources are reporting bloated risk estimates on Zika based on half-truths, faulty assumptions, missing data and invalidated computer models.

The AMA, ABC News and other sources are reporting bloated risk estimates on Zika based on half-truths, faulty assumptions, missing data and invalidated computer models.

(8/26/16 EDITORS NOTE: The CDC has updated their website to state they NOW believe there is a link between zika and microcephaly. However, they still caution by saying: “there is more to learn. Researchers are collecting data to better understand the extent Zika virus impact on mothers and their children.”. The truth check rating “in the shadows” is still valid at this point, since the level of scientific evidence that confirms with high certainty is of low quality. That will be analyzed here soon).

However pregnant women should clearly exercise caution in Zika prone areas.

By David McKalip, M.D.

First a caveat. It is possible that Zika is causing microcephaly more frequently (a severely small brain in babies) and that this represents a major medical and public health problem that needs substantial attention. However, there are still not enough facts to verify this with certainty or to determine the likelihood (risk) that microcephaly will occur during an individual pregnancy or if it is occurring more frequently than in the past or even frequently at all.

Unfortunately the media and the American Medical Association (AMA) have been acting as if a recent risk estimate done by a CDC scientist is valid and can be used to create good policy and justified actions.  An independent analysis of such AMA and media claims on the risks of microcephaly from Zika as is rated as “In the Shadows” by the Sunbeam Times Truth Check. The rating is giving since the claims are deceptive and based on obvious half-truths, lack of data and faulty analysis.

The media and the American Medical Association have been running non-stop stories on Zika. Anecdotal stories usually feature hispanic babies with microcephaly and are shown along with pictures of mosquitoes and pregnant women. The CDC, World Health Organization (WHO) and the government are referred to heavily. This is all done in the atmosphere of all government agencies wanting more funding for their programs and more power to exert population management in the name of safety from a perceived epidemic. The narrative was expanded dramatically this week based on what was inaccurately called a “CDC Warning” that Zika is associated with a “high risk” of microcephaly during pregnancy.


AMA hysteria on microcephaly and Zika riskIn the Shadows: AMA Claim that “Microcephaly risk from Zika high in first trimester, CDC warns”

Why it’s “In the Shadows”: “These estimates are based on a number of assumptions that can’t yet be verified,” Dr. Christina Chambers, codirector of the Center for Promotion of Maternal Health and Infant Development at the University of California, San Diego.

“The findings and conclusions in this article are those of the authors and do not necessarily reflect the official position of the Centers for Disease Control and Prevention”.


“What has been proven here is that percentages can be calculated using a computer program, not the actual risk of microcephaly in women that have Zika.  The logic is circular since it starts off with a formula that says: “If it happens more commonly when the infection rate is low, then the risk of microcephaly is high”. That’s it.” (from conclusion below)

AMA’s False Claim of a “CDC” warning.

The AMA, ABC news and others ran with headlines indicating two claims that are not accurate

1. That the risk of microcephaly is “high” from a Zika infection in the first trimester

2. That the CDC itself is issuing these very dire warnings.

The AMA and many others are not providing an accurate portrayal of the recent study published in the New England Journal of Medicine. First of all, the study is done by researchers who happen to be employees of the CDC. That does not make the study a “CDC warning” as was breathlessly claimed in the AMA headline. The disclaimer on the study by Dr. Michael Johansson and others published in the New England Journal of Medicine is crystal clear:

“The findings and conclusions in this article are those of the authors and do not necessarily reflect the official position of the Centers for Disease Control and Prevention”.

Furthermore, the CDC still has unmistakable guidance on its wesbsite concerning Zika and pregnancy showing that they still do not have anywhere near enough information to draw valid conclusions. (SEE EDITORS NOTE ABOVE ABOUT AN UPDATE TO THE CDC SITE – the information below is from an older version of the CDC website and is now gone). So much so that they say this:

What we do not know (from the CDC website) – AS OF 5/26/16 – see Editors note above.

  • If a pregnant woman is exposed
    • We don’t know how likely she is to get Zika.
  • If a pregnant woman is infected
    • We don’t know how the virus will affect her or her pregnancy.
    • We don’t know how likely it is that Zika will pass to her fetus.
    • We don’t know if the fetus is infected, if the fetus will develop birth defects.
    • We don’t know when in pregnancy the infection might cause harm to the fetus.
    • We don’t know whether her baby will have birth defects.
    • We don’t know if sexual transmission of Zika virus poses a different risk of birth defects than mosquito-borne transmission.

AMA’s false claim on a “high risk” of microcephaly from Zika during pregnancy.

The study referred to by the AMA and major media outlets does not conclusively or even partially provide any valid evidence of a high risk from Zika for microcephaly. As has been done by the media for years, the media – and now sadly the AMA – are inaccurately reporting scientific analysis and estimates as indisputable fact. The study, conducted by scientists employed at the CDC actually is a mathematical estimate of the possibility of a baby becoming microcephalic during pregnancy if the mother is infected with Zika. The study scientists themselves go out of the way to point out that the study has major limitations stating:

“There are uncertainties and limitations with all current estimates of microcephaly risk associated with ZIKV infection. First, available data are very limited, especially in recently affected areas such as Bahia, where infection rates are unknown and microcephaly cases are still being reported and evaluated. The limited information on ZIKV infection rates is compounded by difficulty in the clinical confirmation of microcephaly, as evidenced by low confirmation rates in the independent, temporary microcephaly reporting system established by Brazil in late 2015. Carefully designed serosurveys and data from other locations can help in refining these estimates.”

In addition, Dr. Christina Chambers, a maternal and infant development researcher at the University of California, San Diego indicated how the Johansson report are mere estimates. She said in the “Stat” news article cited by the AMA:  “These estimates are based on a number of assumptions that can’t yet be verified.” Furthermore, the AMA and other reports refer to rates of microcephaly as high as 29% in Brazil based on a study of pregnant women with Zika and suspect ultrasound findings during pregnancy. In fact, no data has been released to demonstrate if these ultrasound findings (many of which were’nt microcephaly) were confirmed after birth. There was also no adequate study of normal women in the area to see what there rate of microcephaly was or what other sources could have caused it (see table 2 in this study).

A look at the report by Dr. Johansson is also instructive. The report does not identify how often actual, verified microcephaly cases occurred. It does not provide a number of microcephaly cases in any population or even an actual number of verified Zika infections in actual pregnant women with microcephalic babies. It does not analyze the possibility that the birth defects were due to another viral infection, another illness, another congenital source or an environmental source like alcohol abuse (a known cause of microcephaly). That is because the Johansson study is merely a computer construct, a virtual reality based on many flawed assumptions that have not yet been proven. No real data was gathered to prove the assertions.

Dr. Johansson’s Zika/Microcephaly Mathematical Model and Estimates

What the Johansson study does is create a mathematical model, based on many assumptions and estimates. It bases these assumptions and estimates on a set of data from an outbreak of Zika in 2007 the French Polynesian islands, and 5,000 miles to the west on the island of Yap, north of Australia. In 2007, the rate of Zika infection was estimated at 66-73% of the population based on a separate study. Dr. Johansson then attempts to estimate the “magnitude of the risk of microcephaly in Brazil” based on a Zika outbreak that occurred in Bahia Brazil in 2015. However, in his own report he states “the infection rate in Bahia cannot be reliably inferred from currently available data”. He then uses the microcephaly rates reported in a separate database in Brazil and puts all of these numbers together in a mathematical model to come up with risk estimates of microcephaly in Brazil occurring during pregnancy. The study also admitted there was no knowledge of how common microcephaly was before Zika became an issue and the condition was monitored.

To be clear here is the source of Dr. Johansson’s mathematical model:

1. Estimated Rates of Zika infections at 66-73% of everyone in French Polynesia in 2007 (extrapolated to the entire population of 7,391 from only 185 sick patients with Zika confirmed in only 49 people, and a blood test showing an infection at some point in the past in about 70% of people when about 550 people were tested)

2. An estimate on the actual rate of Zika infection in Bahia Brazil on the other side of a continent across the pacific from Zap. The estimates were set between 10 to 80% for the rate of Brazilian Zika infections since the actual rate was unknown

3.A database of babies with microcephaly without any verification on the other possible sources of the deformity or if the deformity actually existed or was associated with Zika.

4. An assumed pre-Zika rate of Brazilian microcephaly set low at 2 per 10,000 when the Johansson report indicates it could be as high as 12 per 10,000 before the Zika scare. Thus any number above that would appear to be computer evidence of an infection.

All of these very broad numbers, estimates and assumptions with very little data to back them up were then fed into a computer program that used this very complex formula and statistical calcuations.

johansson microcephaly zika risk formula1johansson microcephaly zika risk formula2

“We fit this model in R (R‐ using Markov Chain Monte Carlo sampling in JAGS (mcmc‐ via rjags (CRAN.R‐ We assigned each pM|Z parameter a naïve Beta prior and used uniform priors for pM0 (2‐12 cases per 10,000 births)”

(From Johannson paper appendix)


The formula calculated alleged risks for microcephaly in pregnant women with Zika based on infections occurring in anywhere from 10-80% of the population (another set of estimates since the rate was unknown). From this rather complex set of assumptions, estimates and formulas a table was created showing what the risk of microcephaly would be if the rate of Zika was present at certain rates in Brazil. The tables estimated the risk for microcephaly to be anywhere from 0.88% to 13.2% based on how common Zika infections might be in Brazil. These tables are computer generated numbers, not actual observed cases of microcephaly and Zika.

Decoding the Zika-Microcephaly risk estimate

What has been done with this risk analysis is very similar to the mathematical modeling done to estimate the chances of global warming in the next several decades using computer models. There is no valid data. There is no lab work and no interview of patients directly. There is no verification that anyone actually had Zika or that the babies actually had microcephaly since these are all phantom people in a computer model.

The best way to decode this would be to recognize that this is circular logic. The estimate of risk is based on how likely a baby is estimated (guessed) to have microcephaly if the population happens to have various rates of infection. Assume 80% of the people of Brazil have a Zika infection and 80 out of 100 pregnant women have Zika. If one of those women had a baby with Zika then this model would say that 1/80 babies got Zika or were “at risk”. That would be 1.25% of babies getting microcephaly from Zika. However, if 10% the women had Zika, and one baby got Zika, that would mean that 1/10 babies would get Zika, putting the risk at 10%. So this is simple math. In other words, if very few people had Zika, and alot of babies had microcephaly, then the risk of the deformity would be high. That is simple math of numerators and denominators.

What has been proven here is that percentages can be calculated using a computer program – not the actual risk of microcephaly in women that have Zika.  The logic is circular since it starts off with a formula that says: “If it happens more commonly when the infection rate is low, then the risk of microcephaly is high”. That’s it.

Conclusion: Science should come before hysteria.

Dr. McKalip, neurosurgeon and author of this analysis interviewed the study author by email throughout the day of 5/25/16. He was very generous with his assistance and is to be congratulated for his openess and scientific collegiality. When Dr. Johansson, author of the Zika report, was asked if he felt the AMA was stretching beyond what his study said by calling the risk “high’, he offered: “Any risk of microcephaly is concerning”. Which begs the question: what risk level should be tolerated for faulty computer models, propaganda and harmful public policy?

A good way to look at this would be how the weather is forecast. We all can agree with an 80-100% chance of rain when a cold front is moving in from area 100 miles away on the radar. That is a proven fact. But it would be laughable to say that there is an 80-100% chance of rain based on weather in islands that might have occurred in 2007 on the other side of the world, using weather equipment that has not been tested, yielding numbers that is plugged into a biased computer formula using circular logic. That is about the same level of confidence that should be given to this forecast from the “Zika and the Risk of Microcephaly study” in the New England Journal of Medicine.

No news organization, and certainly not the AMA, should report that there is a “High risk” of microcephaly in pregnant women who have Zika infections. They should also not mislead America by attributing it to the CDC when it is merely one employee of a massive government agency reporting in a single medical journal. What should have been reported was:  “A mathematical model with many unproven assumptions tells us that some babies might get microcephaly from Zika during pregnancy and that risk could be as low as 1% or as high as 13%. However much more study is needed”.  Sadly, this sort of sober reality is not preferred among the establishment.

However such a headline doesn’t grow the public concern and, yes, the government-induced hysteria. Such a headline will not lead to bigger government and more research grants. Such a headline would not provide justification for a private company to get special exemptions to introduce GMO mosquitos to the environment with unknown and possibly disastrous long term consequences. Such a headline would not allow even more power in the hands of global agencies like the WHO and the UN that are banking on the Olympics and the Zika story to grow their power over people who never elected them and to whom they are not accountable. To be clear, Zika caused microcephaly is real. There is some evidence linking the two, but not enough to draw the dramatic conclusions discussed in public at this time. We must be careful to perform rational science and sound policy-making and to understand the motives of those who are doing otherwise.

Dr. McKalip is a private practice neurological surgeon in St. Petersburg, President of the Florida Chapter of the Association of American Physicians and Surgeons and an experienced clinical and basic science researcher.  The views expressed here are solely his own.