Pediatric HIV Exposure or Infection Linked to S pneumoniae and P jirovecii Carriage Prevalence, Density

Pediatric HIV infection and HIV exposure without infection both had an association with carriage prevalence and densities for Streptococcus pneumoniae and Pneumocystis jirovecii, with a more profound effect for P jirovecii, according to study results published in the Clinical Infectious Diseases.

To examine the effect of children’s HIV exposure and infection status on the nasopharyngeal carriage and carriage density of S pneumoniae and P jirovecii, researchers analyzed data from Zambian children who were part of the Pneumonia Etiology Research in Child Health (PERCH) study. They compared carriage prevalence and density between a case group (with pneumonia) and a control group (without pneumonia), each group comprised 3 HIV exposure groups: children infected with HIV, children who were HIV exposed but uninfected (HEU), and HIV unexposed and uninfected children (HUU).

The study included a total of 1154 children (555 cases and 599 matched controls) with 62% children who were HUU, 24% HEU, and 14% living with HIV. The mean age was 9.6 months, though infants in the case group were younger than infants in the control group (8.4 vs 10.8 months, respectively; P <.01) and were more likely to have a low birth weight (18% vs 12%, respectively; P =.02). Infants in the case group were also more likely to have growth patterns that were stunted, wasted, and underweight compared with the control group.

When stratifying the cohort by HIV exposure status, HEU infants were younger than children living with HIV or HUU children (7.3, 13.2, and 9.6 months, respectively) and had lower birth weights than HUU infants. Although birth weights were similar between children living with HIV and the HEU children, children living with HIV were more likely to be categorized as stunted, wasted, or underweight than the HEU or HUU children.

The S pneumoniae carriage prevalence rates were similar between cases and controls. Among S pneumoniae carriers with pneumonia, carriage density was increased among children living with HIV vs HEU or HUU children (15.8, 4.7, and 3.6 x10⁵ copies/mL, respectively).

Compared with their matched controls, P jirovecii carriage was far more common among children living with HIV and among HEU children. Overall, 31% of children living with HIV tested positive for P jirovecii, compared with 15% of HEU children, and 10% of HUU children. The P jirovecii density showed a graded density relationship comparing children living with HIV to HEU or HUU children (63.9, 20.9, and 4.8 x10³ copies/mL, respectively). Compared with controls, P jirovecii carriage density was also higher among children living with HIV (63.9 vs 0.6 x10³ copies/mL) and HEU children (20.9 vs 0.7 x10³ copies/mL).

In the multivariate analyses, researchers observed a positive association between carriage and age with the oldest children having higher odds of being S pneumoniae carriers (adjusted odds ratio [aOR], 3.48; 95% CI, 2.15-5.62), compared with those in the second (aOR, 2.33; 95% CI, 1.55-3.49) or third quartiles (aOR, 2.70; 95% CI, 1.76-4.15).

In contrast with the relatively weak associations between HIV exposure status and S pneumoniae carriage, the odds of being a P jirovecii carrier were roughly 6-times higher in children living with HIV than in HUU children in the case group (aOR, 6.63; 95% CI, 3.24-13.54). In addition, unlike what was observed for S pneumoniae, P jirovecii carriage showed a strong inverse relationship with children’s age.

Nutritional status in the 3 different measures analyzed (wasting, stunting, and underweight) had only a minimal association with S pneumoniae carriage or carriage density and no consistent or strong association with P jirovecii carriage.

Exposure to cotrimoxazole prophylaxis had a strong negative association with P jirovecii carriage and with reduced P jirovecii carriage density, but only a small association with S pneumoniae carriage density.

“At a higher level, our analysis provides further evidence of fundamental differences in immune functions among HIV exposed but uninfected infants, compared with HIV unexposed infants,” concluded the researchers. “Longitudinal data, capturing points of sickness and health in the same individuals, as well as between exposure groups over time, could be helpful in further exploring this problem,” they added.

Reference

Camelo IY, Mwananyanda LM, Thea DM, Seidenberg P, Gill CJ, Weinstein JR. A tale of 2 pneumos: the impact of human immunodeficiency virus exposure or infection status on pediatric nasopharyngeal carriage of Streptococcus pneumoniae and Pneumocystis jiroveci: a nested case control analysis from the pneumonia etiology research in child health study [published online February 15, 2020]. Clin Infect Dis. doi:10.1093/cid/ciaa164