Following the introduction of PCV7 and later PCV13 in Madrid, Spain, there was a 70% reduction in the incidence of invasive pneumococcal disease in children less than 15 years of age. There was also a pronounced decline in the percentages of penicillin- and cefotaxime-resistant strains of the pneumococcus bacteria. After PCV13 was introduced in 2010, cefotaxime resistance among meningitis patients completely disappeared and both cefotaxime and penicillin resistance among non-meningitis cases declined to very low levels (<3%).
Pneumococcal disease/PCV/PPSV
Introduction of PCV-10 in Mozambique reduced pneumococcal strains in unvaccinated HIV-infected children by 30%
Two years after the introduction of 10-strain pneumococcal conjugate vaccine (PCV-10) in Mozambique, the percent of unvaccinated children under five years of age who carried pneumococcal strains in the vaccine declined 30% among HIV-infected children, while no significant decline in unvaccinated HIV-negative children was seen.
Immunization with PCV10 in Mozambique reduced pneumococcal carriage rates in both HIV-infected and uninfected children
Within two years of the introduction of PCV10 in Mozambique, the percent of vaccinated children under five years of age with nasopharyngeal carriage of vaccine strains, declined equally in HIV-infected as in HIV-uninfected children. The vaccine-type carriage rates among both HIV-infected and uninfected vaccinated children after the vaccine was introduced were similar.
Pneumococcal nasopharyngeal carriage can be a precursor of invasive pneumococcal disease.
High rates of drug-resistant bacteria found in sickle cell disease patients in Ghana
A study of sickle cell disease patients in Ghana found that pneumoccocus bacteria found in their noses and throats had high rates of drug resistance with 37% of positive samples resistant to penicillin and 34% resistant to multiple drugs (typically penicillin + tetracycline + cotrimoxazole).
Childhood vaccination with PCVs reduces the incidence of invasive pneumococcal disease and benefits the whole population
A large study in Norway found that the overall incidence of invasive pneumococcal disease (IPD) declined significantly in individuals on immunosuppressive drugs following the introduction of PCVs for infants — and most significantly in people undergoing chemotherapy. These findings underscore the benefits that childhood vaccination with PCVs affords the entire population.
Immunization reduces the risk of invasive pneumococcal disease, but those on immunosuppressants still have higher chances
Even though the incidence of invasive pneumococcal disease declined in all groups, including individuals on immunosuppressive drugs, following the introduction of pneumococcal conjugate vaccines for infants in Norway, people on chemotherapy were still 20 times more likely to get IPD than individuals not on any immunosuppressants, while individuals on long-term corticosteroids or other immunosuppressive drugs were around 6 times more likely to get the disease.
Introduction of PCV-10 in Kenya reduced pneumococcal bacteria in HIV-positive adults, highlighting benefits of immunization
Two years after the introduction of 10-strain pneumococcal conjugate vaccine (PCV-10) in Kenya, the percent of HIV-positive adults who carried pneumococcal bacteria declined significantly (from 43% to 28%), but did not decline in HIV-negative adults. However, the reduction in carriage of pneumococcal strains that are in PCV10 declined significantly in both HIV-positive and HIV-negative adults. This reduction was still four times higher in HI- positive vs. HIV-negative adults (2.8% vs. 0.7%), indicating that HIV positive adults continue to be at considerably higher risk of invasive pneumococcal disease than HIV-uninfected adults.
Nasopharyngeal carriage is an indicator of the risk for invasive pneumococcal disease and pneumonia
The PCV-13 vaccine may increase the susceptibility of antibiotic-resistant bacteria strains
A community-based study in Vietnam found a high percent of children under five years of age were carrying pneumococcal bacteria in their noses and throats that were non-susceptible to commonly-used antibiotics. Of the strains tested, 18% were not susceptible to penicillin, 26% weren’t susceptible to cefotaxime, 76% were not susceptible to meropenem and 14% were not susceptible to all three nor to any of the “macrolide” drugs (e.g., erthromycin and azithromycin). However, 90% of the multi-drug resistant strains are serotypes that are in the 13-strain pneumococcal conjugate vaccine (PCV-13) and thus the introduction of a vaccine is expected to increase the susceptibility of circulating strains of the bacteria.
Influenza vaccines reduce antibiotic use by preventing secondary infections and unnecessary prescriptions for respiratory illnesses
Vaccines against influenza reduce the use of antibiotics that drive drug resistance in bacteria in two ways. First, they prevent secondary bacterial infections caused by influenza, such as pneumonia and otitis media; in Ontario, Canada, the rate of prescribing for influenza-associated antibiotics declined around 64% after universal introduction of influenza vaccination compared to other Canadian provinces with more limited use of the vaccine. Second, they help prevent inappropriate antibiotic prescriptions for respiratory tract infections caused by influenza and other viruses, which account for half of all respiratory illnesses for which antibiotics are prescribed in the U.S.
Continuing vaccination in Kenya will prevent thousands of deaths and be cost-effective
An analysis in Kenya found that, although the government will need to more than double its current vaccine budget to continue using PCV after GAVI support ends, continuing the vaccination will prevent more than 101,000 cases of invasive pneumoccocal disease and pneumonia, more than 14,000 deaths over an 11-year period, and would be cost-effective (cost per DALY of $153 by 2032), even at the full GAVI price of US $3.05 per dose.