Immunizing pregnant women protects infants from influenza, with 56% efficacy in the first 2 months of life

A pooled analysis of three randomized controlled trials conducted in Nepal, Mali, and South Africa between 2011 and 2014 found that immunization during pregnancy provided protection against influenza to young infants from birth through 4 months of age. Protection against infant influenza was greatest in the first 2 months of life, with 56% efficacy, and the pooled efficacy of maternal vaccination to prevent infant laboratory-confirmed influenza up to 6 months of age was 35%.

Immunization during pregnancy reduces the risk of miscarriages, stillbirths, low birthweight, and premature deliveries

Studies from multiple Western countries have found that pregnant women infected with influenza during the 2009 A/H1N1 pandemic were at higher risk of miscarriages, stillbirths, low birthweight and premature deliveries. The risk of fetal death was between 2 and 5.5 times higher in pregnant women with influenza than in pregnant women without influenza. In the UK, the rate of stillbirths was 4.5 times higher and the likelihood of preterm delivery was 4 times greater in influenza-infected pregnant women than non-infected women.

Although this article indicated that influenza vaccination is safely used for the mother and the fetus, conflicting data exists on the effect of vaccination in improving preterm birth rates.

Influenza vaccination during pregnancy reduces severe pneumonia rates in infants, especially during peak influenza circulation

An analysis of data from three studies showed that the rates of severe pneumonia in infants in their first six months of life was 20% lower overall in infants whose mothers received the influenza vaccination during pregnancy than in infants whose mothers had not, and the rates of severe pneumonia was 56% lower during periods when influenza circulation was highest. These findings correspond with evidence that influenza infection predisposes individuals to pneumococcal infection.

The incidence rate of severe pneumonia in the vaccine group compared to the control group was 43% lower in South Africa, 31% lower in Nepal, but not significantly different in Mali.

Empowering women can lead to greater vaccination rates in children

In a systematic review of qualitative research from low- and middle-income countries, women’s low social status was shown to be a barrier to their children accessing vaccinations. Specific barriers included access to education, income, resource allocation, and autonomous decision-making related to time. The authors suggest that expanding the responsibility for children’s health to both parents (mothers and fathers) may be one important element in removing persistent barriers to immunization often faced by mothers.

Undernourished children have a higher likelihood for diarrhea and pneumonia but immunization can improve infant growth

Multiple studies show that

  1. Diarrhea and pneumonia impair children’s growth and that underlying malnutrition is a major risk factor for these conditions.
  2. “Episodes of diarrhea may predispose to pneumonia in undernourished children” and
  3. Immunization against influenza (in mothers) and Streptococcus pneumoniae may improve infant growth. In addition, new studies from Bangladesh, Colombia, Ghana, and Israel further support the paradigm that malnutrition is a key risk factor for diarrhea and pneumonia.

Bacterial meningitis is associated with long-term neurophysiological impacts

A systematic literature review analyzing data from 21 African countries revealed that bacterial meningitis is associated with high case fatality and frequent neurophysiological sequelae. Pneumococcal and Hib meningitis contribute to one third of disease related mortality. They also cause clinically evident sequalae in 25% of survivors prior to hospital discharge. The three main causes of bacterial meningitis- Haemophilus influenzae type B; Streptococcus pneumoniae (pneumococcus) and Neisseria meningitidis (meningococcus) are vaccine preventable, routine use of conjugate vaccines have potential for significant health and economic benefits.

Neuropsychological sequelae includes hearing loss, vision loss, cognitive delay, speech/language disorder, behavioural problems, motor delays/impairment, and seizures.