Pneumonia hospitalizations of children aged <2 years in Poland before (2013–2016) and after (2017–2018) universal mass vaccination with 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine

Figures & data

Figure 1. Plain language summary.

Table 1. Characteristics of the children (aged <2 years) hospitalized with pneumonia in two Polish hospitals during 2013–2018.

			Opole N=3,049	Bialystok N=1,119	Total N=4,168
Year of birth^a n (%)^b		Pre-UMV	2,450 (80.5%)	960 (85.8%)	3,410 (81.9%)
		Post-UMV	595 (19.5%)	159 (14.2%)	754 (18.1%)
Sex^a n (%)^b		Female	1,248 (41.0%)	383 (34.2%)	1,631 (39.2%)
		Male	1,797 (59.0%)	736 (65.8%)	2,533 (60.8%)
Admission at hospital n (%)^b		Pre-UMV	1,933 (63.4%)	745 (66.6%)	2,678 (64.3%)
		Post-UMV	1,116 (36.6%)	374 (33.4%)	1,490 (35.7%)
Age at admission (months)^a		Mean (SD)	8.8 (6.7)	10.1 (6.7)	9.1 (6.7)
		Median (Q1, Q3)	7 (3, 14)	10 (4, 16)	8 (3, 15)
Pneumonia discharge ICD-10 diagnosis codes n (%)^b	Bacterial pneumonia	J13	2 (0.1%)	2 (0.2%)	4 (0.1%)
		J14	2 (0.1%)	0 (0.0%)	2 (0.0%)
		J15	593 (19.4%)	853 (76.2%)	1,446 (34.7%)
		J85.1	0 (0.0%)	0 (0.0%)	0 (0.0%)
		J86	1 (0.0%)	0 (0.0%)	1 (0.0%)
	Viral pneumonia	J10.0	10 (0.3%)	2 (0.2%)	12 (0.3%)
		J11.0	0 (0.0%)	0 (0.0%)	0 (0.0%)
		J12	374 (12.3%)	220 (19.7%)	594 (14.3%)
		J12.0	0 (0.0%)	1 (0.1%)	1 (0.0%)
		J12.1	211 (6.9%)	216 (19.3%)	427 (10.2%)
		J12.2	0 (0.0%)	0 (0.0%)	0 (0.0%)
		J12.3	0 (0.0%)	0 (0.0%)	0 (0.0%)
		J12.8	61 (2.0%)	1 (0.1%)	62 (1.5%)
		J12.9	102 (3.3%)	2 (0.2%)	104 (2.5%)
	Other type pneumonia	J16	9 (0.3%)	2 (0.2%)	11 (0.3%)
		J17	0 (0.0%)	0 (0.0%)	0 (0.0%)
		J18	2,048 (67.2%)	40 (3.6%)	2,088 (50.1%)
	Non-pneumonia	J10.1	7 (0.2%)	0 (0.0%)	7 (0.2%)
		J10.8	2 (0.1%)	0 (0.0%)	2 (0.0%)
		J11.1	1 (0.0%)	0 (0.0%)	1 (0.0%)

^aInformation was missing for four children of Opole.

^b% = (n/N) x 100, N = total number of hospitalized children in a given region, and n = number of hospitalized children in a given category.

Abbreviations: ICD-10, International Classification of Diseases 10^th revision; Q, quartile; SD, standard deviation; UMV, universal mass vaccination.

Figure 2. Incidence rate of pneumonia hospitalizations among children aged <2 years in two Polish cities by year (2013–2018).

Abbreviation: ICD-10, International Classification of Diseases 10^th revision.

Table 2. Estimated percentage change and effect of universal mass vaccination with 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine on the incidence rate of pneumonia hospitalizations among children aged <2 years in two Polish hospitals (inferential model).

Endpoint^a	Percentage change			Effect
	Estimate	95% CI	p-value	Estimate, cases per 100,000 PY	95% CI
Radiograph-confirmed likely bacterial pneumonia	−13.10%	−54.59%, 66.32%	0.6716	−1.24	−5.17, 6.28
ICD-10-coded bacterial pneumonia	−28.48%	−41.60%, −12.41%	0.0012	−40.58	−59.28, −17.68
ICD-10-coded viral pneumonia	−35.36%	−54.32%, −8.52%	0.0138	−17.61	−27.05, −4.24
ICD-10-coded all-cause pneumonia	−24.60%	−33.89%, −14.01%	<0.0001	−95.50	−131.56, −54.36
Radiograph-confirmed likely non-bacterial pneumonia	−24.98%	−34.50%, −14.06%	<0.0001	−91.56	−126.48, −51.55

^aVariable: eligible for UMV, not eligible for UMV. Reference group: not eligible for UMV.

Note: To model the effect of the PHiD-CV implementation in the UMV program, the incidence rate was modeled via an inferential model using a negative binomial distribution; this included variables to control for the time trend in months, UMV eligibility status by year of birth, region, admission seasonality, seasonality of birth and age in months.

Abbreviations: CI, confidence interval; ICD-10, International Classification of Diseases 10^th revision; PHiD-CV: 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine; PY, person-years; UMV, universal mass vaccination.