Effectiveness of 23-Valent Polysaccharide Pneumococcal Vaccine and Changes in Invasive Pneumococcal Disease Incidence from 2000 to 2017 in Those Aged 65 and Over in England and Wales

Abstract

Background Invasive Pneumococcal Disease (IPD) is a major public health concern. The effectiveness of 23-valent polysaccharide pneumococcal vaccine (PPV23) against IPD in older age-groups is not fully understood. We measured PPV23 effectiveness against IPD and interpreted changes in IPD incidence between 2000 and 2017. Methods Public Health England conducts enhanced national IPD surveillance in England and Wales. The indirect cohort method was used to estimate PPV23 effectiveness against IPD in individuals aged ≥ 65 years eligible for PPV23 vaccination during 2012–2016. IPD incidence in 2016/17 was compared to rates during 2000–2003, when neither PPV23 nor pneumococcal conjugate vaccines (PCVs) were routinely used in England and Wales. Findings PPV23 effectiveness, irrespective of time since vaccination, was 27% (95% CI, 17–35) after adjusting for age, co-morbidity and year of infection. Vaccine effectiveness reduced non-significantly (p = 0.13) with time since vaccination, from 41% (95% CI, 23–54) for those vaccinated within two years, to 34% (95% CI, 16–48) for those vaccinated 2–4 years previously, and 23% (95% CI, 12–32) for those vaccinated ≥ 5 years previously. Vaccine effectiveness did not vary significantly by age but was highest in previously healthy individuals (45%; 95%CI, 27–59). IPD incidence for PPV23 serotypes not included in the PCVs did not decrease after routine PPV23 use but increased significantly since PCV introduction in 2006. Interpretation PPV23 offers moderate short-term protection against IPD in older adults. PPV23 serotypes comprise an increasing proportion of IPD cases in older adults because of serotype replacement following routine PCV use in children. Funding European Union's Horizon 2020.

A Systematic Review of Studies Published between 2016 and 2019 on the Effectiveness and Efficacy of Pneumococcal Vaccination on Pneumonia and Invasive Pneumococcal Disease in an Elderly Population

“…The authors found reduced VE of PPV23 by time since vaccination, with only the first two years since vaccination having a statistically significant VE (Table S3). The UK IPD surveillance study also reported a lower VE point estimate for PPV23 as the time since vaccination increased [22]. However, although the point estimate decreased from 41% for those vaccinated within two years to 23% for those vaccinated more than five years ago, the VE against VT-IPD remained statistically significant also after five years (Table S3).…”

“…For PPV23 we identified one cohort study from Germany [20], one TND study from Japan [21], one indirect cohort study from United Kingdom (UK) [22] and three case-control studies from Spain [23], Japan [24] and South Korea [25], respectively ( Table 1). The German cohort study included almost 739,000 inhabitants aged ≥60 years, retrospectively, using routine insurance data collected between 2010 and 2011.…”

“…The study from UK included 9847 IPD cases from the enhanced national surveillance of IPD in England and Wales. Among these, 6245 (63%) had available vaccination information, and were included in VE analysis using the indirect cohort (Broome) method, with 4423 VT IPD cases and 1822 non VT-IPD controls [22]. The case-control study from Spain recruited 1895 CAP cases and an equal amount of controls from 20 different hospitals between 2013 and 2015 [23].…”

“…VE of the PPV23 vaccine was reported on the following outcomes: all-cause pneumonia [20], CAP [23,24], non-bacteremic pneumococcal pneumonia (NBPP) [25], VT-NBPP [25], pneumococcal pneumonia [21] and VT-pneumonia [21], IPD [25] and VT-IPD [22,25] (Table 1).…”

“…Five studies on PPV23 [20][21][22][23]25] reported VE stratified by age groups (Table 3). For PPV23 there seems to be a decreasing VE with increasing age, and only one study [22] reported a significant VE in the oldest age group (≥85 years). For PCV13, one study showed decreasing VE by age results [16], while another did not find any difference [17] (Table 3).…”