Pneumococcal vaccination for HIV-infected individuals in Singapore

Abstract

Streptococcus pneumoniae (the pneumococcus) is a major cause of morbidity and mortality in both children and adults globally. 1 Colonisation of the nasopharynx by the pneumococcus is the major prerequisite for disease, and in most people is asymptomatic. 2 Dissemination of the bacterium into the surrounding mucosal tissues can cause a range of diseases that are typically classified as either non-invasive such as otitis media, sinusitis and pneumonia or invasive pneumococcal disease (IPD) when it enters a normally sterile site, including bacteraemia (sepsis), meningitis and bacteraemic pneumonia. The major risk factors for the development of pneumococcal disease are age, ethnicity and immune status. Children under five years of age as well as older adults over the age of 65 years are most susceptible. In adults, pneumococcal bacteria are the most frequent cause of community-acquired pneumonia (CAP). This is particularly true for places like Australia and Singapore where there is an ageing population and increased rates of CAP, making this a public health priority. In Singapore, pneumonia is the third leading cause of death, accounting for 16% of total deaths in 2011. 3 Even more significant are younger adults who are immunocompromised, such as those with human immunodeficiency virus (HIV) infection, who are at greater risk for susceptibility to recurrent pneumococcal infections and for which pneumococcal vaccination coverage remains low. HIV infection substantially increases the risk of pneumococcal disease It has long been recognised that HIV-infected adults have a substantially higher risk of acquiring pneumococcal disease (>100-fold) than age-matched HIV-uninfected adults. 4-6

Characterization of bacterial and viral pathogens in the respiratory tract of children with HIV-associated chronic lung disease: a case‒control study

“…The major risk factors associated with the development of pneumococcal disease are demographic (age and sex) and immune status (CD4 count and HIV viral load) [57]. We observed no association between these common factors and most bacterial species, including SP.…”

Vaccine strategies to reduce the burden of pneumococcal disease in HIV-infected adults in Africa.

“…In many high-income countries PCV is recommended for use as priming of HIV-infected adults followed by a PPV23 booster [ 52 , 73 , 74 ], which acts only against IPD. This is despite the limited PCV serotype disease incidence in these settings as a result of effective herd effects from infant PCV programs [ 75 ].…”

“…PCV is more immunogenic than PPV23 [ 23 , 57 , 65 , 69 ] and efficacious in preventing recurrent episodes of VT-IPD in HIV-infected adults [ 65 ]. As per existing recommendations in many high-income countries [ 51 , 52 ], a single dose of PCV followed by a PPV23 booster for expanded serotype coverage could be given to HIV-infected adults in low-income countries to prevent VT-IPD [ 73 , 74 ]. As PCV is efficacious in vaccinees with low CD4+ cell count [ 65 ], it could be given immediately at HIV diagnosis to increase PCV coverage [ 93 ].…”

Characterization of bacterial and viral pathogens in the respiratory tract of children with HIV-associated chronic lung disease: a case–control study

“…The major risk factors associated with the development of pneumococcal disease are demographic (age and sex) and immune status (CD4 count and HIV viral load) [ 64 ]. We observed no association between these common factors and most bacterial species, including SP.…”