The role of influenza, RSV and other common respiratory viruses in severe acute respiratory infections and influenza-like illness in a population with a high HIV sero-prevalence, South Africa 2012–2015

Abstract

Background Viruses detected in patients with acute respiratory infections may be the cause of illness or asymptomatic shedding. Objective To estimate the attributable fraction (AF) and the detection rate attributable to illness for each of the different respiratory viruses Study design We compared the prevalence of 10 common respiratory viruses (influenza A and B viruses, parainfluenza virus 1–3; respiratory syncytial virus (RSV); adenovirus, rhinovirus, human metapneumovirus (hMPV) and enterovirus) in both HIV positive and negative patients hospitalized with severe acute respiratory illness (SARI), outpatients with influenza-like illness (ILI), and control subjects who did not report any febrile, respiratory or gastrointestinal illness during 2012–2015 in South Africa. Results We enrolled 1959 SARI, 3784 ILI and 1793 controls with a HIV sero-prevalence of 26%, 30% and 43%, respectively. Influenza virus (AF: 86.3%; 95%CI: 77.7–91.6%), hMPV (AF: 85.6%; 95%CI: 72.0–92.6%), and RSV (AF: 83.7%; 95%CI: 77.5–88.2%) infections were associated with severe disease., while rhinovirus (AF: 46.9%; 95%CI: 37.6–56.5%) and adenovirus (AF: 36.4%; 95%CI: 20.6–49.0%) were only moderately associated. Conclusions Influenza, RSV and hMPV can be considered pathogens if detected in ILI and SARI while rhinovirus and adenovirus were commonly identified in controls suggesting that they may cause only a proportion of clinical disease observed in positive patients. Nonetheless, they may be important contributors to disease.

Attributable Fraction of Influenza Virus Detection to Mild and Severe Respiratory Illnesses in HIV-Infected and HIV-Uninfected Patients, South Africa, 2012–2016

“…A statistically significant association of influenza virus detection with illness among patients with SARI has also been reported ( 7 , 10 , 11 ). Nonetheless, other studies reported that respiratory syncytial virus but not influenza virus detection was associated with pneumonia in children ( 8 , 9 ).…”

Epidemiology of Acute Lower Respiratory Tract Infection in HIV-Exposed Uninfected Infants

“…39 Point estimates of relative risk for hospitalization in HEU compared with HUU infants for all 3 viruses with a high etiologic fraction that were evaluated (RSV, hMPV, and influenza) were similar to the overall estimate for LRTI, although the incidence was not statistically significantly elevated for influenza, possibly because of the small numbers of cases of influenza included. 40 A nationwide study from South Africa found that HEU patients aged <6 months had 3 to 4 times increased incidence of invasive pneumococcal disease, compared with HUU infants. 39 Bacterial coinfection may have contributed to some of the observed increase in hospitalization and in-hospital mortality in patients with confirmed viral infection; however, the numbers of patients testing lytA-positive with available HIV infection and exposure information (n = 16) were too few to explore this hypothesis or make any firm conclusions about pneumococcal epidemiology in HUU.…”

“…Interpretation of incidence and case-fatality ratios for viruses with a low etiologic fraction is challenging. 40 Studies have shown an elevated mortality in HEU infants aged <6 months. 7 This elevated mortality as well as the observed increased risks of hospitalization in our study may be the result of immunologic deficits that have been documented in HEU infants.…”

Deaths Associated with Respiratory Syncytial and Influenza Viruses among Persons ≥5 Years of Age in HIV-Prevalent Area, South Africa, 1998–20091

“…Studies conducted in Kenya and South Africa that compared the RSV prevalence among patients hospitalized with severe acute respiratory illness (SARI) to control groups found that RSV infection was associated with hospitalization among children <5 years of age, but no association was found among persons >5 years of age (31,32). This finding may suggest that, although RSV is detected among older children and adults, it may play a less important role as a pathogen in this group.…”