A study in rural Kenya, over a 4-year period following the introduction of the 10-strain pneumococcal conjugate vaccine for infants, that included a catch-up vaccination campaign for children 12-59 months of age, suggests that the catch-up vaccination for older birth cohorts may have been a key factor in protecting unvaccinated individuals and speeding up the reduction of the disease in the community. In contrast, a study in The Gambia, where no catch-up campaign took place, found no herd effects during the first three years following the introduction of PCV-13 for infants.
The Gambia study publication referenced can be found at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4909992/
A study of the 10-strain pneumococcal conjugate vaccine in rural Kenya demonstrated herd protection. Over a 4-year period following the introduction of the vaccine for infants, coupled with a “catch-up” campaign for all children 12-59 months of age, the incidence of invasive pneumococcal disease (IPD) caused by the strains in the vaccine fell by 100% in infants less than two months of age who were too young to be vaccinated. In adults (≥ 15 years old) the incidence of IPD fell by 81% and in 5-14 year olds the incidence fell by nearly 75%. The chances of unvaccinated persons becoming ill with any strain of the disease also fell significantly – by 87% in infants under two months old, by nearly half (47%) in 5-14 year olds, and by more than one-third (37%) in adults.
Three studies in Bangladesh and India found that the direct medical costs for children hospitalized with pneumonia were 27% to 116% of the average monthly income of households. And, while these costs represent a major portion of a family’s monthly income, they don’t include non-medical costs, such as transport and food costs, nor the lost wages of family members who miss work to care for the child.
In a global review of the costs of treating childhood pneumonia, the average costs of a hospitalized case of pneumonia in children under five years of age was US$243 in primary or secondary hospitals in low- and middle-income countries (ranging from US$40 – US$563) and US$559 in tertiary hospitals (ranging from US$20 – US$1,474). In high-income countries, the cost of hospitalized cases averaged US$2,800 in primary or secondary hospitals and more than US$7,000 in tertiary hospitals. Note that in most of these studies, only direct medical costs were included and thus total costs – including non-medical costs and lost wages – would be considerably higher.
One of the first studies of real-world use of pneumococcal conjugate vaccine (PCV) in Africa, found 48% fewer cases of pneumonia in children confirmed by x-ray after PCV introductoin. The results show the vaccine greatly reduced childhood pneumonia hospital admissions in Kenya: Hospital admissions for pneumonia went down 27%.The vaccine led to 329 fewer pneumonia cases per 100,000 kids each year.
In New Zealand, Maori and Pacific children have historically suffered high hospitalization rates for invasive pneumococcal disease (IPD), all cause pneumonia (ACP), and otitis media. Following the introduction of conjugate vaccines in the country, Maori and Pacific children’s rates of admission for IPD dropped by 79% and 67%, respectively, while significant reductions in ACP and otitis media admissions were also noted, resulting in reductions in disparities for these populations.
Children under 5 years of age bear the greatest burden of indirect conflict-associated mortality (indirect mortality results from disruption of health services including immunization, food insecurity, and high risk living conditions such as those found in refugee camps). The leading causes of child death in these circumstances include respiratory infections, diarrhea, measles, malaria, and malnutrition.
In a Bangladeshi study, pneumonia and acute diarrhea were the first and third most common reasons for childhood hospital admission with over half (54%) of the acute diarrhea admissions caused by rotavirus. One in four children taken to this large pediatric hospital were refused admission because all beds were occupied. Vaccination could have prevented children with rotavirus from requiring essential hospital resources when one in four children refused admission had symptoms of pneumonia.
Findings of a systematic review evaluating the relationship between pneumonia and malnourishment found that severely malnourished children in developing countries had 2.5 to 15 times the risk of death. For children with moderate malnutrition, the risk of death ranged from 1.2 to 36.
A study modeling the relationship between disease and poverty in Ethiopia found that among the top 20 causes of death in Ethiopia, diarrhea and lower respiratory infections (LRIs) are the top two drivers of medical impoverishment. It is estimated that in 2013, out-of-pocket direct medical costs for diarrheal disease drove an estimated 164,000 households below the poverty line (representing 47% of all the diarrhea cases), and LRIs led to an estimated 59,000 cases of poverty (17% of LRI cases). Of the top 10 health-associated drivers of poverty, four are at least partially vaccine-preventable (1. Diarrhea, 2. LRI, 4. TB. 10. Pertussis).
