By Ewen Callaway
This summer, Eritrea, Côte d’Ivoire and Niger will join a growing list of countries where infants receive a vaccine to prevent pneumonia, meningitis and other deadly diseases caused by the pneumococcus bacterium (Streptococcus pneumoniae). Pneumonia is a leading killer of young children in low-income countries; vaccinations from 2010 to the end of this year are estimated to have averted 500,000 deaths, according to the GAVI Alliance in Geneva, an international organization that facilitates vaccination.
Data from South Africa also point to another benefit of vaccination: stemming a rising tide of antibiotic resistance in the developing world. The country’s introduction of a pneumococcal conjugate vaccine (PCV) in 2009 has not only reduced the overall incidence of invasive pneumococcal disease by about two-thirds in infants (the age group vaccinated) and in adults, but has also reduced penicillin-resistant infections in both groups.
This is the first time such benefits have been observed outside the developed world. The data should spur public-health officials in low-income countries that have not yet adopted the vaccine to start using it, says Anne von Gottberg, a clinical microbiologist at the National Institute for Communicable Diseases in Johannesburg and leader of the study (see ‘Protecting children’). Her group has reported the results at conferences but they have not yet been published.
The problem of antibiotic resistance is particularly stark in low-income countries, where over-prescription and poor regulation combine with a higher disease burden and poor sanitation to increase the use of antimicrobial drugs. A recent survey by the World Health Organization found rates of resistance in Klebsiella pneumoniae as high as 54%. Reduced susceptibility of Streptococcus pneumoniae to penicillin was found worldwide, and topped 50% in some reports.
In North America, Europe and other well-off parts of the world, the introduction of pneumococcal vaccines in the early 2000s reduced cases of invasive pneumococcal disease by more than one-third in vaccinated children and in unvaccinated adults, who typically acquire infections from children. The vaccine also reduced the numbers of serious pneumococcal infections that were resistant to front-line antibiotics such as penicillin.