Vaccine slashes pneumonia cases

South Africa's introduction of a new childhood vaccination against pneumococcal diseases five years ago has slashed the incidence of life-threatening pneumonia and meningitis, according to a study published in the New England Journal of Medicine.

Business Day, 12 November 2014

The rate of Invasive Pneumococcal Disease (IPD) caused by strains of bacteria covered by the shots fell 90 percent in children under the age of 2, and 57 percent in adults aged between 25 and 44. IPD refers to severe diseases caused by pneumococcal bacteria, such as meningitis, pneumonia, and sepsis. Overall the rate of IPD in the population fell 40 percent.

SA was the first African country to add shots against pneumococcal bacteria to its national immunisation programme for babies, so the study's findings provide important confirmation that this was a sound policy decision, said study co-author Cheryl Cohen, an epidemiologist at the National Institute of Communicable Diseases. She said that while there is good evidence of the vaccine's effectiveness from the US, until now there has been limited data from developing countries to support its use. The study shows the vaccine can have a major impact in a developing country with a high burden of HIV/AIDS and pneumonia, she said, noting that the vaccine was introduced to tackle SA's high child mortality rate.

But the study also highlighted the benefits of childhood vaccinations for the rest of the population. Pneumonia is the leading cause of death in children under the age of five worldwide and is responsible for more than 1.1million deaths a year, according to the World Health Organization. It kills more children than HIV/AIDS, tuberculosis and malaria combined. While most healthy children can fight off pneumonia-causing pathogens, children who are malnourished or infected with HIV are highly vulnerable.

The Department of Health initially provided Pfizer's PCV7 vaccine, branded Prevnar, which gave protection against seven strains of pneumococcal bacteria. It later switched to PCV13, which protects against 13 strains. The researchers compared the incidence of laboratory-confirmed cases of IPD before and after the introduction of Prevnar, using a baseline period between 2005 and 2008 and a post-vaccine period of 2011-12. They found the overall rate of IPD among children under the age of two declined from 54.8 cases per 100 000 of population a year to 17 cases per 100 000 of population, but that it declined from 32.1 to 3.4 cases per 100 000 of population a year for diseases caused by the strains of bacteria covered by PCV7. The rate of IPD caused by strains of bacteria covered by PCV-7 in adults aged between 25 and 44 fell from 3.7 to 1.6 cases per 100 000 population a year.