THE BLOG
02/29/2016 04:47 pm ET Updated Mar 01, 2017

When Zika Turns Deadlier: How Anti-Vaccination Misinformation Could Exacerbate an International Health Emergency

The world is in a frenzy over the Zika virus. Researchers established a link between its rise in Brazil and cases of congenital microcephaly in babies of infected pregnant women, with infants born with smaller than expected heads and improper brain development. As of November last year, Brazil's northeastern state of Pernambuco recorded 646 babies born with microcephaly. On February 1, the World Health Organization (WHO) declared the virus and its suspected link to birth defects an international public health emergency.

Though we don't yet understand the exact relationship between Zika and microcephaly, there is clear cause for concern. But even more troubling is a virus brewing beneath the surface: rumors circulating online that this birth abnormality is actually caused by the Tdap vaccine given to pregnant women. It's not. When the anti-vaxxer movement meets a global health pandemic, the consequences could be dire.

Zika does carry potential dangers for expectant mothers and their babies. But the virus is tame compared to its local counterparts -- dengue is nicknamed "break-bone fever," chikungunya "bending-up fever." But it is really tame compared to tetanus, diphtheria, and pertussis, the bacterial infections against which Tdap protects.

Tetanus affects the brain and nervous system, causing painful muscle spasms that can be strong enough to make it impossible to open one's mouth. It kills one in five infected. Diphtheria causes difficulty breathing and can lead to heart and nerve damage. Pertussis, otherwise known as whooping cough, is a respiratory infection that can result in serious breathing problems. It is very contagious, and particularly dangerous for infants, with severe cases resulting in pneumonia, seizures, brain damage, or death.

The danger to babies of contracting these infections, particularly pertussis, has led the Centers for Disease Control (CDC) to recommend that all pregnant women be vaccinated in their third trimester to help protect a newborn in the first months of life. Lest we think that it is only big public health agencies that send out these messages, the American College of Obstetricians and Gynecologists and the American College of Nurse-Midwives, which specialize in caring for pregnant women, echo this recommendation.

Tdap provides early and much-needed protection for infants. The mother's body uses the vaccine to create protective antibodies that are then passed onto the baby before birth. The first months of a baby's life present the greatest risk, particularly for contracting whooping cough, both in terms of risk for infection and severe, life-threatening complications from the disease. Pertussis might start like a cold, with a mild cough or runny nose, but within one to two weeks, children can start struggling for breath after a coughing fit, making "whooping" sounds. Babies may gag and gasp. It might be difficult to breath, eat, drink, or sleep, with a cough getting severe enough to cause vomiting or a lack of oxygen.

It's easy to understand why we would want to prevent these diseases if we could.

In 2014, the CDC recorded 32,971 cases of pertussis in the United States. Between 2000 and 2014, there were 277 deaths from whooping cough; 87 percent were babies younger than 3 months old.

But compare this to numbers before vaccines became widely available. Back in the 1940s, about 200,000 children were infected with whooping cough each year in the United States, with 9,000 deaths resulting. Tetanus infected and killed several hundred per year. Diphtheria was the third leading cause of death in children in England and Wales in the 1930s, with nearly half of those infected dying from the disease.

Vaccines have dramatically curtailed rates of pertussis, and nearly eradicated cases of tetanus and diphtheria in the U.S. Although work remains to be done on the international stage, huge progress has been made. As of 2014, 86 percent of children around the world were immunized against diphtheria, tetanus, and pertussis. The WHO estimates that immunization of these along with measles saves two to three million people every year.

Despite this progress, almost 19 million infants worldwide are not given basic vaccines. The reasons for this are many: limited resources, poor health systems, or competing priorities. But the results are tragic. Each year, there are an estimated 16 million cases and 195,000 deaths from whooping cough around the globe. Progress achieved by vaccinating against infectious diseases is encouraging. We can't afford a backslide caused by dangerous distortions peddled by the anti-vaccination movement.

Many critics thus far have rightly taken aim at Latin American countries that are encouraging women to avoid pregnancy while Zika rages, but denying or limiting their access to birth control or abortion. Imagine this tragedy compounded by thousands of cases of preventable diseases brought on by unfounded fears of vaccination.

We may think the great danger in this crisis is Zika. But global health organizations like the CDC and WHO need to be mindful of more insidious threats in their midst. It is one thing to fight a virus. It is another to fight misinformation.