Clinical effectiveness of pneumococcal vaccination against acute myocardial infarction and stroke in people over 60 years: the CAPAMIS study, one-year follow-up

Table 3 Numbers needed to vaccinate for preventing one case of community acquired pneumonia, acute myocardial infarction or ischaemic stroke by pneumococcal vaccination in people 60 years or older

Outcome	Attributable Risk per 1000 person/year		Number Need to Vaccinate
	AR^a	95% CI^b	NNV^c	95% CI (lower to higher^d)
Community acquired pneumonia	1.067	-1.139 to 3.327	938	306 to -878
Acute myocardial infarction	0.423	-1.341 to 2.187	2,365	458 to -746
Ischaemic Stroke	1.788	0.177 to 3.399	560	295 to 5649

^a Attributable Risk = incidence rate difference between unvaccinated and vaccinated subjects.
^b CI denotes confidence interval.
^c NNV is the number needed to vaccinate for preventing one case and is estimated as 1/AR.
^d The negative numbers in the high limit of confidence interval indicate that NNV tends to infinite and it is not statistically significant.

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