Twenty-Year Public Health Impact of 7- and 13-Valent Pneumococcal Conjugate Vaccines in US Children

Matt Wasserman; Ruth Chapman; Rotem Lapidot; Kelly Sutton; Desmond Dillon-Murphy; Shreeya Patel; Erica Chilson; Vincenza Snow; Raymond Farkouh; Stephen Pelton

Disclosures

Emerging Infectious Diseases. 2021;27(6):1627-1636. 

In This Article

Results

IPD

Among children <5 years of age, the annual number of IPD cases decreased from ≈16,000–18,000 during 1997–1999 to 1,382 in 2019 (Table 1; Figure 1, panel A). We estimated that PCVs averted a cumulative 282,558 cases of IPD during this timeframe. Of those averted cases, we estimated that 146,455 were prevented by PCV13 during 2010–2019. Among children <5 years of age, annual deaths caused by IPD decreased from 126–202 during 1997–1999 (Table 1) to 85 in 2019. We estimated that PCVs prevented a total of 2,780 deaths during this timeframe, including 1,402 deaths prevented by PCV13 during 2010–2019.

The overall IPD incidences in the input ABCs data were generally higher than in the sources used for validation. However, the ABCs and the Kaiser Permanente data[30] reflected similar overall trends for the pre-PCV and PCV7 eras; the ABCs and data from Yildrim et al.[31] reflected similar overall trends for the PCV7 and PCV13 eras. The differences were probably caused by variations in reporting and patient groups between data sources; the ABCs data are more nationally representative and therefore more generalizable than the population described by Black et al..[30]

We observed a decrease in IPD-related deaths after the introduction of PCV7; however, we could not identify whether this trend existed during the pre-PCV period because of limited data (Table 1). Pulido et al.[35] described a declining IPD mortality rate during 1990–2005, supporting the ABCs data and indicating that deaths were already decreasing before the introduction of PCVs. Reductions in smoking rates and implementation of laws regarding smoking in public places, shifts from inpatient to outpatient care settings, improved treatments, and varying case definitions might have also contributed to the declining trend.

We estimated that during 2000–2019, PCVs prevented 172,778 cases of bacteremia; 55,532 cases of bacteremic pneumonia and empyema; 16,660 cases of meningitis; and 37,017 cases of other forms of IPD (Figure 2). IPD cases caused by PCV13 serotypes decreased from 14,439 cases in 1997 to 396 in 2019 (Table 2; Figure 1, panel B). During 2000–2019, PCVs are estimated to have averted 286,302 IPD cases caused by vaccine serotypes. During this period, IPD cases caused by non-PCV13 serotypes increased slightly, consistent with modest serotype replacement.

OM Healthcare Visits

The average rate of OM visits among children <5 years of age declined from 78/100 to 46/100 children per year from the pre-PCV (1997–1998) to the PCV13 era (2011–2013). In other words, these visits declined by 39%, from 15,000,483 in 1997 to 9,112,727 in 2019 (Figure 1, panel C). We estimated that PCVs averted a cumulative 97,326,688 OM-related healthcare visits (Table 3).

The overall visit numbers in the input data[23] were generally lower than in the sources used for validation,[32–34] but the overall trends for the pre-PCV and PCV7 eras were comparable. The differences might have been caused by varying database populations, because Zhou et al.[23] used national data whereas Marom et al.[32] and Tong et al.[33] mainly considered privately insured patients who might have been more likely to seek care. Therefore, the estimates from Zhou et al.[23] are probably more representative on a national level.

Pneumonia Hospitalizations

Annual pneumonia hospitalizations in children <5 years of age declined from 113,116–175,420 in 1997 to 37,882 in 2019. We estimated that PCVs averted a cumulative 438,914–706,345 pneumonia hospitalizations, including 216,303 cases caused by PCV13 serotypes, during the 20 years after PCV introduction in the United States (Table 4).

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