Changes in pneumococcal carriage prevalence and factors associated with carriage in Norwegian children, four years after introduction of PCV13

Table 3 Univariable and multivariable multilevel logistic regression analyses between any pneumococcal carriage and factors previously associated with carriage; data of the 2006, 2008, 2013 and 2015 surveys were included

Factors previously associated with carriage	Univariable: Odds Ratio (OR) [95%CI]	p-value^b	Multivariable: Odds Ratio (OR) [95%CI]^c	p-value^b
Year of the study sample		< 0.001	–	–
2006	3.9 [2.9–5.1]
2008	4.5 [3.4–6.0]
2013	1.8 [1.5–2.2]
2015	1
Age in months		< 0.001		< 0.001
< 24	1		1
24–35	0.99 [0.74–1.3]		0.94 [0.70–1.3]
36–47	0.74 [0.56–0.98]		0.61 [0.46–0.82]
48–59	0.54 [0.41–0.70]		0.41 [0.31–0.54]
> = 60	0.39 [0.29–0.52]		0.31 [0.22–0.40]
Cohabiting with siblings < 6 years old		0.204		0.402
No	1		1
Yes	1.1 [0.95–1.3]		1.1 [0.91–1.3]
Breastfed < 2 months		0.567		0.665
No	1		1
Yes	1.1 [0.78–1.6]		1.1 [0.76–1.5]
Passive smoking		0.685		0.895
No	1		1
Yes	1.1 [0.81–1.4]		0.98 [0.73–1.3]
Vaccinated		< 0.001	–	–
PCV7	1
PCV7 + 13	0.60 [0.45–0.80]
PCV13	0.98 [0.79–1.2]
Unvaccinated	1.9 [1.5–2.4]
Vaccine history^d		< 0.001		< 0.001
No	1		1
Yes	0.50 [0.39–0.64]		0.37 [0.29–0.47]
RTI^a last 3 months		< 0.001	–	–
No	1
Yes	0.58 [0.44–0.76]
Use of antimicrobials last 3 months		< 0.001		< 0.001
No	1		1
Yes	0.48 [0.37–0.64]		0.42 [0.32–0.57]
Size of day care centre		0.1905		0.7132
10–29 children	1		1
30–49 children	1.3 [0.79–2.0]		1.2 [0.80–1.7]
50–69 children	1.3 [0.81–1.9]		1.1 [0.80–1.6]
70–89 children	1.6 [0.98–2.4]		1.2 [0.82–1.7]
90+ children	2.0 [1.1–3.5]		1.4 [0.89–2.2]

^aRTI Respiratory tract infection
^bSignificance for linear and binary variables was tested using single parameters Wald-tests; significance for categorical variables with more than two categories was tested using multiple parameter Wald-tests
^cIn the multivariable model we included the following variables: age in months, cohabitating with siblings < 6 months, breastfed < 2 months, passive smoking, vaccine history, use of antimicrobials last 3 months and size of day care centre
^dVaccine history was defined as being vaccinated with any PCV (yes/no; at least one dose), independent of vaccine type

ISSN: 1471-2334