Pneumococcal disease is a significant cause of morbidity and mortality. HIV-infected adults have a 35-fold greater risk of invasive pneumococcal disease than the general population. As a result, in 2012, the United States ACIP recommended the 13-valent pneumococcal conjugate vaccine (PCV-13) for HIV-infected adults. Pneumococcal nasal carriage is thought to precede pneumococcal disease. Studies have shown that vaccination of children with pneumococcal conjugate vaccines can decrease pneumococcal nasal carriage both in vaccinated children and in unvaccinated members of their community. However, there is no data in the literature on the effect of the introduction of PCV-13 into the United States childhood vaccination schedule in 2010, or on the effect of direct PCV-13 vaccination, on pneumococcal nasal carriage rates in HIV-infected adults.
This was a prospective observational clinical study on adults with well-controlled HIV infection who had received or were scheduled to receive PCV-13 at the Eastern Virginia Medical School HIV clinic from 2013-2014. We collected nasal swabs from 105 subjects just prior to PCV-13 receipt, 100 of whom returned for a second nasal swab 4-6 weeks after the first visit. We also collected nasal swab from 50 additional subjects 11-13 months after PCV-13 receipt. Nasal swabs were stored and plated for pneumococcal isolation according to the World Health Organization protocol.
Only one of the 255 nasal swabs from 155 subjects grew pneumococcus, for a nasal carriage rate of 0.64%. The single pneumococcal isolate was from a subject who had received PCV-13 one-year prior and was a non-vaccine serotype. Our subjects were all on antiretroviral therapy with a median CD4 count of 606 cells/mm3.
Our study demonstrates very low pneumococcal nasal carriage rates in adults with well-controlled HIV infection 3 years after PCV-13 introduction into the childhood vaccination schedule in the United States. These results were irrespective of direct PCV-13 vaccination amongst our subjects. Further studies are needed to determine if invasive pneumococcal disease in this population has also been affected by PCV-13 introduction.
A. Rossheim, None
S. Troy, None