People living with HIV continue to be at increased risk of invasive pneumococcal disease,
Danish investigators report in the online edition of Clinical Infectious Diseases. Even in the era of modern
antiretroviral therapy, risk of the infection was 19-fold higher among
people living with HIV compared to matched controls in the general
People living with HIV who inject drugs had an especially high
risk of invasive pneumococcal disease, and the authors sugges, “[people who inject drugs] might be
an important target group for pneumococcal immunization, since they had the
highest susceptibility to the disease over time in spite of the availability of
Streptococcus pneumoniae is an important cause of serious bacterial disease in people living with HIV, and rates of invasive pneumococcal disease have been reported to be
up to 100 times higher among people living with HIV compared to the general
Denmark wanted to see if the availability of effective HIV therapy and the
introduction in 2007 of a childhood pneumococcal immunisation programme using a
conjugate vaccine had reduced rates of invasive pneumococcal disease in people living with HIV.
compared rates of the disease between people living with HIV and matched
controls. The study period was 1995 to 2012, which was divided into three periods
to reflect developments in HIV treatment and care: 1995-96, pre-combination
antiretroviral therapy (cART); 1997-99, early cART; 2000-12, modern cART.
Each participant living with HIV was matched with 19 controls from the general Danish population.
pneumococcal disease was diagnosed by either blood culture or cerebrospinal
population comprised 5362 people living with HIV and 101,869 matched controls.
Invasive pneumococcal disease was diagnosed in 137 people living with HIV and 136 controls.
The people living with HIV were younger than the controls at the time of diagnosis
with the disease (40 vs 47 years) and were less likely to be diagnosed with
meningitis (4% vs 10%).
Comparison between people living with HIV with and without invasive pneumococcal disease showed
that those with the infection were more likely to be female (32% vs 24%, p =
0.03), have a history of injecting drug use (26% vs 10%, p < 0.001), have a
lower current CD4 count (303 vs 338 cells/mm3, p = 0.05) and a
lower nadir CD4 count (116 vs 183 cells/mm3, p < 0.001).
The incidence of
invasive pneumococcal disease was 205 cases per 100,000 person-years of
follow-up for people living with HIV compared to 13 cases per 100,000 person years
of follow-up for the controls.
Overall risk of
invasive pneumococcal disease was approximately 24-fold higher among people living
with HIV compared to the controls (IRR = 23.7; 95% CI, 22.9-24.4, p <
Risk of the
disease declined among people living with HIV as antiretroviral therapy improved,
but even in the modern HIV treatment era the risk remained significantly higher
for people living with HIV compared to the controls (IRR = 18.9; 95% CI, 14.3-25.00,
p < 0.001). Moreover, the risk of the disease remained unchanged throughout
the study period for people living with HIV who inject drugs.
Among people living
with HIV, smoking (RR = 1.34; 95% CI, 1.26-1.42, p < 0.001) and injecting
drug use (RR = 2.51; 95% CI, 2.26-2.67, p < 0.001) were associated with an
increased risk of pneumococcal disease. Risk of the infection was also
increased by the presence of detectable viral load (RR = 1.88; 95% CI, 1.79-1.98,
p < 0.01) and lower CD4 cell count.
mortality rate was lower for people living
with HIV compared to the controls (7% vs 14%). Age was the only independent
risk factor associated with death.
“The incidence of
invasive pneumococcal disease in HIV-infected individuals remained
significantly higher than the incidence observed in HIV-uninfected individuals,
in spite of the widespread use of cART in Denmark,” conclude the authors. “[People who inject drugs]
have a remarkably high risk of invasive pneumococcal disease that hasn’t
declined over time, and remain an obvious group for targeted
immunization…injecting drug use, smoking and the receipt of cART are suitable
targets for preventative measures.”