Table 3. Number of pertactin-deficient Bordetella pertussis isolates in study countries in the EUpert IV collection, Europe, 2012–2015 (n = 66 isolates).
| Country | Number of PRN-deficient isolates in EUpert IV | Number of isolates collected in EUpert IV | Frequency of PRN-deficient isolates (%) in EUpert IV (95% CI) | Number of PRN-deficient isolates in EUpert III | Number of isolates collected in EUpert III | Frequency of PRN-deficient isolates (%) in EUpert III (95% CI) | EUpert IV vs. EUpert III (p value) | Year of ACV introduction for primary vaccinationa |
|---|---|---|---|---|---|---|---|---|
| Sweden | 20 | 29 | 69.0 (50.8–82.7) | 1 | 19 | 5.0 (0.9–23.6) | <0.001 (increase) | 1996 |
| Italy | 11 | 20 | 55.0 (34.2–74.2) | NA | NA | NA | NA | 1995 |
| Norway | 10 | 32 | 31.3 (18.0–48.6) | 5 | 20 | 25.0 (11.2–46.9) | 0.7574 | 1998 |
| United Kingdom | 8 | 30 | 26.7 (14.2–44.5) | 0 | 20 | 0.0 (0.0–16.1) | 0.0155 (increase) | 2004 |
| France | 5 | 29 | 17.2 (7.6–34.6) | 3 | 20 | 15.0 (5.2–36.0) | 1.0000 | 2004 |
| Denmark | 4 | 27 | 14.8 (5.9–32.5) | 0 | 23 | 0 (0.0–14.3) | 0.1147 | 1997b |
| Belgium | 4 | 38 | 10.5 (4.2–24.1) | NA | NA | NA | NA | 1999 (Flanders) / 2002 (Wallonia) |
| Netherlands | 3 | 32 | 9.4 (3.2–24.2) | 0 | 20 | 0 (0.0–16.1) | 0.2760 | 2005 |
| Finland | 1 | 28 | 3.6 (0.6–17.7) | 0 | 16 | 0 (0.0–19.4) | 1.0000 | 2005c |
ACV: acellular pertussis vaccine; CI; confidence interval; FHA: filamentous haemagglutinin; NA: not available; PRN: pertactin; PT: pertussis toxin.
a The years in this column are given for the introduction of a PRN-containing ACV except if otherwise stated.
b In Denmark, solely PT-based vaccine in use from 1997.
c In Finland, vaccine containing PT and FHA was first used, and PRN was included in 2009.