Comparative analysis of Streptococcus pneumoniaetransmission in Portuguese and Finnish day-care centres

BMC Infectious Diseases

Table 2 Acquisition and clearance of Streptococcus pneumoniae carriage in a day-care centre in Portugal, 1998–1999

The crude estimates of the model parameters are (cf. Appendix): the transmission rate $\hat{β} = (39 - \hat{κ} \times 374) / 60.18 = 0.54$ (per month); the community acquisition rate per serotype (in non-carrying children) $\hat{κ} = 22 / 1236 = 0.018$ (per month); the clearance rate of carriage $\hat{μ} = 55 / 165 = 0.33$ (per month); the competition parameter $\hat{ϕ} = (24 / 1687) / (22 / 1236) = 0.80$ . For parameter β, the denominator (60.18) is not directly readable from the data as presented in the table. Only samples available from two consecutive visits were considered, accounting for 67% of the scheduled pairs of consecutive visits. The three rooms were analysed as six rooms, separated by the summer break.
¹ Exposure is here defined as the presence of at least one carrier of the target serotype in the other attendees in the room.
² Person-time here is the total time, in months, spent carrying pneumococcus overall (total row) or a specific serotype (serotype rows) stratified by the presence or absence of other carriers of the specific serotype.
³ Person-time here is the total time, in months, spent as a non-carrier, stratified by exposure to the specific serotype. For the total row, the time is a sum of serotype-specific person-times.
⁴ As in ² but for children carrying pneumococcus.

ISSN: 1471-2334