Vaccine coverage should begin during pregnancy, says researcher
New parents-to-be see and hear a host of messages geared toward them. Breastfeeding is best. Rear-facing, not front-facing, car seats are safer for newborns. Babies should sleep on their backs. What parents aren't hearing enough, says RSPH researcher Saad Omer, is that pregnant women and their babies need vaccines so that both stay healthy.
"When you start talking about childhood vaccines with parents after their babies are born, it is already too late," he says. "Young parents are more receptive when they are pregnant. There are already lots of messages that are targeted to them during pregnancy, such as breastfeeding and safety. We need to add mother and child vaccinations to that."
He wants pregnant women to know that vaccinations given during pregnancy also help protect their babies. He was the first researcher to document that babies born during flu season (October 1 to May 31) and whose mothers were vaccinated during pregnancy were less likely to be premature or small for their gestational age than babies born to unvaccinated mothers. Another of his studies demonstrated that vaccinating pregnant women against influenza also protected their infants.
"Vaccinating pregnant women is especially important in developing countries," he says. "Here in the United States, premature babies go to the NICU. In many parts of developing countries, there is no NICU. Worldwide, 1 million deaths are associated with preterm births."
Omer's findings helped lead the World Health Organization to recommend the use of the influenza vaccination globally, especially among pregnant women. He currently is heading up a study in Pakistan, the first one in the world to look at pertussis vaccination of pregnant women and the impact on their infants.
But what affects a woman's decision to get a vaccination for herself or her child? Omer has shown that the key is a woman's relationship with her health care provider. Women are more likely to get vaccinated during pregnancy and more likely to have their children vaccinated if their health care provider recommends doing so.
"Health care providers are the most trusted source of immunization information," Omer says. "How physicians approach vaccination with parents has an impact on vaccination update rates. If vaccination is treated as a routine part of care, then children are more likely to get boosters."
Vaccine noncompliance, or vaccine refusal, raises everyone's risk of disease, he notes. "Vaccine-preventable diseases such as measles, influenza, and pertussis often start among persons who forego vaccinations, spread rapidly within unvaccinated populations, and also spread to other subpopulations."
In California, officials attributed a 2010 pertussis outbreak to waning immunity from vaccines. But Omer and his colleagues were the first to determine that, in fact, areas with high rates of children entering kindergarten with a nonmedical exemption for vaccines were 2.5 times more likely to be living in a pertussis cluster. The state's rate of nonmedical exemption more than tripled during the 10 years prior to the outbreak.
Today, approximately 3% of U.S. parents are hard-core vaccine skeptics, according to studies. Another 25% are "fence-sitters," who may decline some but not all child vaccines, and they should be the focus of the public health community, Omer says. "We don't want them to move into the refusal group."
What helps keep them out of the refusal group is a wearisome exemption policy, one that requires several steps, not simply checking a box on a form. States with easier exemption policies have higher rates of infectious disease than those with a multistep process, Omer says. "We want to nudge the balance of convenience."
His research on the California pertussis outbreak helped inform policies in other states.
"The bottom line is that vaccines are still one of the most effective tools we have for preventing disease in children," he adds. "Maintaining high levels of vaccine coverage will help ensure that we keep the progress we've made in eradicating or warding off childhood diseases."
