Two bacteria between them killed approximately 900,000 children in the year 2000, with another 8 million infected, often with devastating consequences. A study of the distribution of vaccines against Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (pneumococcus) has found they have been central to reducing this toll by two-thirds. Millions of lives over the next decade depend on getting vaccines to the places where they are lacking.
Detractors often accuse IFLScience of sounding like a broken record when it comes to criticizing anti-vaccination campaigners. If so, there's a good reason. The number of lives vaccines save is beyond most people's comprehension, and even small interruptions to access have insanely disastrous consequences.
A new paper in The Lancet Global Health calculates the benefits provided by these two vaccines, and proposes how they can be best deployed in future. "Further progress against these diseases will depend on efforts in a few large countries," said Dr Brian Wahl of Johns Hopkins University in a statement.
Despite its name, Hib doesn't cause influenza, which is a viral disease. It was thought to be the cause of the flu for forty years and the name stuck. Moreover, most of the deaths it causes are when the immune system is weakened from fighting other things, including Orthomyxoviruses, the real cause of flu, and other viruses such as HIV.
The introduction of a vaccine against Hib in the early 1990s largely eliminated the disease from rich countries. Unfortunately, the vaccine is substantially more expensive than those against other common childhood diseases, which delayed its distribution in poorer countries.
A vaccine against pneumococcus has existed since the 1980s. Although several improved versions have come out since, their use was rare in low-income countries until 2009.
The two bacteria are the main causes of meningitis worldwide, and commonly induce pneumonia and sepsis among other serious conditions.
The Lancet study compiled data from all low-income countries on meningitis and pneumonia deaths, and combined these with estimates of the proportion attributable to these bacteria. From 299,000 and 600,000 for the two diseases in 200, deaths have plunged to 29,500 and 294,000 in 2015. Most of the 1.45 million livers saved were in the last few years, indicating a tremendous unnecessary death toll in the first decade of the millennium.
Such numbers can easily fog one's brain, but they mean that in 2015 alone the children whose lives were saved would more than fill most countries' largest stadium six times over or replace a decent-sized city. Although the vaccines were not the whole story, better hygiene and access to health care also contributed, Wahl said the evidence showed the vaccines were the biggest factor.
Most remaining Hib and pneumococcus deaths are in four countries – India, Nigeria, Pakistan and the Democratic Republic of Congo – where large regions have low vaccination rates.