Children vaccinated with three doses of pneumococcal conjugate vaccine had a reduced rate of human metapneumovirus-associated infections of the lower respiratory tract, as well as a lower rate of clinical pneumonia than children given placebo, researchers reported.
Dr. Shabir A. Madhi of the University of the Witwatersrand, Bertsham, South Africa, and colleagues performed an analysis of data from nearly 40,000 children—some of whom had been infected with HIV—who had been given three doses of a polysaccharide-protein conjugate vaccine (PCV) or placebo in an ongoing phase III study.
Dr. Madhi and coinvestigators tested nasopharyngeal aspirate samples of the children who had been hospitalized with lower respiratory tract infection (LRTI) for evidence of human metapneumovirus (hMPV), which was discovered only 5 years ago, as well as for HIV and C-reactive protein (J. Infect. Dis 2006;193:1236–43).
They found that for vaccinated children without HIV infection, the hospitalization rate was 46% lower than that of children who received placebo. For HIV-infected children, the reduction was 53% versus placebo. The incidence of clinical pneumonia also was reduced for both HIV-free and HIV-infected children who received vaccine (55% and 65%, respectively).
These results “suggest that bacterial coinfections, particularly pneumococcal infections, are an essential part of the pathogenesis of most severe hMPV infections progressing to pneumonia,” they said. This means that children hospitalized with hMPV-associated pneumonia “should be treated with antibiotics.”