The Region of the Americas is a leader in vaccinating pregnant women against influenza, a public health problem that for future mothers, newborns, and other high-risk populations can mean severe disease, complications, and hospitalization. In all, 32 of the Region’s 52 countries and territories, which contain the majority of the Region’s women, vaccinate pregnant women to protect them from influenza, an acute viral infection that is transmitted from person to person.
Influenza epidemics cause between 3 million and 5 million cases of severe disease, and some 250,000 to 500,000 deaths worldwide each year. In the Americas, between 40,000 and 160,000 people are estimated to die yearly as a consequence of the disease, the majority of victims being over the age of 65.
“Vaccination is the most effective way of preventing the disease and its serious consequences for pregnant women, as well as for fetus and newborn,” said Cuauhtémoc Ruiz, chief of the Comprehensive Family Immunization Unit of the Pan American Health Organization (PAHO), which is the World Health Organization’s (WHO) Regional Office for the Americas. “Influenza vaccines are safe and effective, and have been used for over 70 years,” said Ruiz-Matus.
Pregnant women are especially susceptible to complications from influenza because of physiological changes in the cardiopulmonary and immune systems that occur with pregnancy. The older the woman, the higher the risk of severe disease and hospitalization as a result of influenza infection. Similarly, women with other diseases who get influenza are more likely to need intensive care.
Finally, influenza during pregnancy can cause fetal death, premature delivery, low birthweight, or babies born small for their gestational age.
Vaccination during pregnancy protects the fetus through mother-to-child transmission of high concentrations of antibodies. Various studies show that the risk of death during the first year of life for children of mothers who had influenza during pregnancy is almost double the risk for children born of mothers who did not have influenza.
WHO recommends annual vaccination for pregnant women in any stage of pregnancy. In addition, it recommends vaccinating the other high-risk populations against influenza: children between the ages of 6 months and 5 years; older adults; patients with certain diseases, such as HIV/AIDS, asthma, chronic pneumopathies, and chronic heart disease; and health professionals.
In 2015, 40 of the 52 countries and territories of the Region had influenza vaccination policies in effect. The first country of the continent to introduce the vaccine was the United States in the 1940s. It was followed by Canada and Bermuda in the 1970s, Chile in 1975, and the rest of the countries from the 1990s on. In 2004, only three countries vaccinated pregnant women, in 2008 seven, and in 2010 seventeen.
It was after the A (H1N1) influenza pandemic of 2009, when high disease burden and mortality were found among pregnant women, that the number of countries vaccinating pregnant women against influenza increased from 7 countries to 32 countries.
Despite the widespread introduction of influenza vaccination for pregnant women in the Region, regional coverage is approximately 59%, with large variations from country to country, according to information that 19 countries of the Americas provided PAHO.
“We must make greater efforts to increase vaccination coverage to at least 95 percent to protect women, and babies under 6 months old, who cannot be vaccinated before this age,” said Alba María Ropero, PAHO/WHO regional advisor on immunization. “This can be achieved by solid health systems that routinely include maternal immunization as a part of prenatal care, by health professionals’ taking a greater role, and by promoting awareness of the benefits of vaccination on the part of pregnant women,” she said.
PAHO recently published a Maternal and Neonatal Immunization Field Guide for Latin America and the Caribbean with key information on the maternal and neonatal vaccines that are available or in development. It provides the countries of the Region with recommendations on introducing or expanding the use of these vaccines.