Pregnant Women

PIVI encourages partner countries to place a particular emphasis on vaccinating pregnant women against seasonal flu.

PIVI encourages partner countries to place a particular emphasis on vaccinating pregnant women against seasonal flu. This emphasis is consistent with a 2012 report from the WHO Strategic Advisory Group of Experts (SAGE) on Immunization titled “Background Paper on Influenza Vaccine and Immunization SAGE Working Group.” The report lists pregnant women as the highest priority of the five populations considered at high risk for developing severe disease. According to the report:

“Pregnant women should be vaccinated against influenza at any stage of pregnancy. In countries considering initiating or expanding vaccination programs for influenza, SAGE recommends pregnant women as the highest priority group for vaccination. This recommendation is based on compelling evidence of a substantial risk of severe disease in pregnant women, evidence that vaccine is effective against severe disease, and the evidence supporting secondary protection of infants under 6 months, in whom disease burden is also high, as well as operational feasibility.”

How exactly does flu affect pregnant women and infants?

According to the data reviewed by SAGE, “influenza is responsible for substantial morbidity and mortality in pregnant women. In the US, half of hospitalizations for otherwise healthy pregnant women in their third trimester during the influenza season have been attributed to seasonal influenza viruses.” Evidence shows that “pregnant women are at a particularly high risk of severe complications and death from influenza and the risk is exacerbated by co-morbidities and later trimester of pregnancy.”  Severe complications can include bronchitis, pneumonia, and ear or sinus infections. Conditions that place an individual at risk of severe complications from flu can include diabetes, obesity, and asthma. The SAGE report notes that, “during the 2009 H1N1 pandemic, pregnant women without other “high-risk” co-morbidities [diabetes, asthma, obesity] were approximately twice as likely to be hospitalized for influenza infection as compared to nonpregnant women (71% vs. 32%).

Not only are pregnant women themselves at risk of health complications, flu can also adversely affect the baby. “The primary impacts on neonates from severe maternal infection with seasonal or pandemic influenza virus are preterm birth, low birth weight, and decreased weight for gestational age.”

Is the flu vaccine safe for pregnant women or their babies? Does it make a difference?

SAGE is joined by a number of medical and public health organizations, including the American College of Obstetricians and Gynecologists (ACOG), CDC, and the UK’s National Health Service to name just a few, in its conclusion that the influenza vaccine – both seasonal and pandemic – is safe for pregnant women. In fact, the ACOG writes that “the preponderance of data overwhelmingly demonstrate the safety of influenza vaccination during pregnancy.” While many of the studies that have contributed to these organizations’ decisions and recommendations were done in the US, studies conducted in developing countries have also concluded that the flu vaccine is safe for pregnant women. A study published by Zaman, et al. in the New England Journal of Medicine in 2008 that looked at the clinical effectiveness of influenza vaccine given to pregnant women in Bangladesh found that the vaccine “reduced proven influenza illness by 63% in infants up to 6 months of age and averted approximately a third of all febrile respiratory illnesses in mothers and young infants.”

Studies show the vaccine is safe for pregnant women, but what about the baby? Infants under 6 months old are not eligible to receive the influenza vaccine. From birth until about 6 months, infants rely on passive immunity (that is, immunity initially gained in utero) for protection from disease. When a pregnant woman is vaccinated against influenza, the baby also reaps the benefits: research has shown that the antibodies generated by the flu vaccine provide the baby with protection against the flu for the first several months of life – giving the baby protection until she is able to vaccinated herself. The ACOG affirms that “maternal influenza immunization offers demonstrated disease prevention benefits for women and their newborns and is a critically important component of prenatal care.”

PAHO Flu Vaccination Coverage for Pregnant Women 2013Is anyone else doing anything about this? If there are recommendations, and some countries even provide free vaccine, why aren’t more pregnant women getting vaccinated?

Some countries have committed to the WHO recommendation regarding pregnant women by creating national policies. For example, in the Americas, most countries have policies recommending (and providing) influenza vaccination for pregnant women. The map to the right shows coverage among pregnant women in Central and South America.

Despite the recommendations from a number of public health and medical organizations that encourage pregnant women to be vaccinated against seasonal influenza, globally coverage among pregnant women is suboptimal. Factors like vaccine hesitancy, perceived risks of vaccination, a lack of information about the vaccine, whether or not a woman’s doctor/medical provider recommends the vaccine, and accessibility all play a role in coverage rates.

In some cases, the cause is simply a lack of information. In settings where medical providers and healthcare workers are uninformed about the influenza vaccine, its composition, its benefits (as well as its risks), and its importance, patients are unlikely to learn about or want the vaccine. Uninformed healthcare professionals ultimately lead to uninformed patients and communities. Studies on influenza vaccine uptake and pregnant women have shown that provider recommendations are one of the top reasons a pregnant woman will choose to be vaccinated against the flu.

In addition to a lack of knowledge about influenza and its vaccine, perceived risks and/or vaccine myths can contribute significantly to providers’, communities’, and individuals’ hesitancy to be vaccinated against the flu. A 2014 WHO SAGE report on Vaccine Hesitancy highlights three main causes of general vaccine hesitancy, all of which apply to the flu vaccine. These include:

“1) Beliefs, attitudes, motivation about health and prevention,

2) risk/benefit of vaccines (perceived risks, experiences (heuristics)), and

3) communication and media environment.”

The report also notes that “major [vaccine hesitancy issues] were fear of side effects of vaccination and distrust in the vaccine, lack of perceived risk of vaccine-preventable diseases, and the influence of anti-vaccination reports in the media.

Myths and the media can both play a key role in keeping pregnant women from being vaccinated against flu. Ultimately, though, these factors will differ by culture and are important to take into consideration when countries are trying to reach pregnant women with influenza vaccination. PIVI is addressing these issues through its post-introduction evaluations, which identify knowledge, attitudes, and perceptions about the flu vaccine at various levels of the vaccine distribution/administration process. The PIEs can identify knowledge gaps and help country partners to make sure to address those gaps. As a result, not only will healthcare providers be better informed, their patients will also be better informed.

Finally, effective influenza vaccination programs are best carried out by a combination of EPI and Maternal and Child Health (MCH) or Antenatal Care (ANC) teams, since MCH and ANC teams may be more effective advocates for maternal immunization. Otherwise, pregnant women may not be considered a priority group and may miss out on the opportunity to be vaccinated. PIVI encourages its partner countries to involve multiple groups when planning and executing flu vaccination programs. Sharing knowledge and resources can help strengthen both immune systems and infrastructure.

 


Sources

World Health Organization SAGE Working Group: Background Paper on Influenza Vaccines and Immunization
American College of Obstetricians and Gynecologists: Committee on Obstetric Practice and Immunization Expert Work Group
Effectiveness of Maternal Influenza Immunization in Mothers and Infants, Zaman, et al.
Pan American Health Organization
World Health Organization SAGE Working Group: Report of the SAGE Working Group on Vaccine Hesitancy