Fact or Fiction: Is there a link between microcephaly and vaccines?

CALGARY  – It’s a frightening time to be pregnant. Outbreaks of Zika virus in Latin America and the Carribean have many Canadian moms-to-be cancelling sunny vacations over concerns that an infection could put their baby at risk.

A suspicious link between Zika’s arrival in Brazil last year and a surge in the number of babies born with microcephaly have prompted travel warnings for those expecting. Last week, the World Health Organization declared a state of international emergency over Zika virus but an online theory now circulating on social media is suggesting something other than Zika virus is to blame.

The headline of one such article reads, “The Real Cause of Birth defects in Brazil: Zika or Improper vaccine use?” on another site, the question,  “Brazilian Shrunken Head Babies: Zika or T-Dap?”

In each post, the authors point out that cases of microcephaly appeared to increase in Brazil along the same time that country began immunizing pregnant women with a vaccine that offers protection against tetanus, diptheria and whooping cough (T-Dap).

READ MORE: What pregnant women need to know about Zika virus and travel

An Alberta health official says the theory isn’t based on fact.  “There is no link between whooping cough or whooping cough immunization and microcephaly,”  Dr. Gerry Predy, Alberta Health Services Senior Medical Officer of Health, said in a statement.

University of Calgary Infectious disease specialist, Bonnie Meatherall agrees.  “A number of studies are continuing to look at this.  A couple of papers have just come out in early 2016 and (the research) doesn’t seem to show a link between T-Dap received in pregnancy and any concerns for the development of birth defects of any kind.”

A New Zealand study published last month in the British Medical Journal followed over 400 babies whose mother’s were given the T-Dap vaccine during pregnancy. According to the study’s abstract, the research found,  “no significant differences in birth weight, gestational age at birth, congenital anomalies or infant growth as compared with baseline population data.”

While vaccines have not been linked to microcephaly,  Meatherall says a number of vaccine preventable illnesses are.

“We know rubella can cause microcephaly that’s a well-known link and chicken pox is associated with poor outcomes as well.”

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Rubella, also known as German measles, is an infection that can lead to fever, sore throat and swollen glands.  If a woman is infected with rubella during pregnancy, the virus can cause congenital birth defects impacting the baby’s brain, eyes, heart and other organs.  According to Immunization Canada, before the measles, mumps and rubella (MMR)  vaccine was introduced in the late 1960s, there were large epidemics of rubella about every seven years.  In one major epidemic in the US, nearly 30,000 babies were infected, more than 8,000 died and 20,000 were born with birth defects.

Both rubella and chicken pox are vaccine preventable, however, it is not safe for women to receive these vaccine during pregnancy because they contain live viruses.  That’s why, health officials recommend women ensure their immunization records are up to date before they conceive.