Parainfluenza Virus Infection Among Human Immunodeficiency Virus (HIV)-Infected and HIV-Uninfected Children and Adults Hospitalized for Severe Acute Respiratory Illness in South Africa, 2009–2014

Cohen, Adam L.; Sahr, Philip K.; Treurnicht, Florette; Walaza, Sibongile; Groome, Michelle J.; Kahn, Kathleen; Dawood, Halima; Variava, Ebrahim; Tempia, Stefano; Pretorius, Marthi; Moyes, Jocelyn; Olorunju, Steven A. S.; Malope-Kgokong, Babatyi; Kuonza, Lazarus; Wolter, Nicole; von Gottberg, Anne; Madhi, Shabir A.; Venter, Marietjie; Cohen, Cheryl

It can be difficult to attribute respiratory disease to a specific pathogen. Molecular tests may identify viruses in respiratory specimens that may not be causing illness, and coinfection with other potentially pathogenic respiratory viral infections was common in our population. We found that a majority of SARI was attributable to PIV types 1 and 3 in children, even when controlling for viral respiratory coinfection, but not all studies have found that PIV is pathogenic. In fact, very few studies have adequately evaluated PIV in the context of controls. Two studies from Kenya that compared patients with respiratory illness to controls did not find a statistically significant attributable risk for PIV [6, 12] . However, a study comparing children <5 years of age from Thailand hospitalized with pneumonia to controls found findings similar to ours, specifically that infection with PIV types 1 or 3 was associated with disease [25] . The lower incidence and nonsignificant AF from our data among individuals ≥5 years of age suggests that PIV infection may not be associated with respiratory disease in older children and adults. We did not find a significant AF for patients infected with PIV type 2, but we may not have been powered to detect this because type 2 was the least common type. We found differences among patients infected with different types of PIV and between patients infected and uninfected with HIV. In children, patients with PIV-associated SARI who were HIV-infected were more likely to be older and to be coinfected with pneumococcus; however, the AF among adults was not statistically significant. The association between respiratory viral and pneumococcal infection, although not described previously for PIV infection, is well described for other pathogens such as influenza [26] and RSV [27] . Pneumococcal conjugate vaccine was introduced in the South Africa childhood immunization system in 2009, so it was available and being used during the entire time of this study.