Rubella: 2010 Epidemiological Data
In 2010, the network comprised 296 laboratories covering the entire country, including 286 in mainland France (8 in the Overseas Departments and 2 in the Overseas Territories). The participation rate of the laboratories surveyed was 87% (laboratories participating in both survey semesters), with 98% of laboratories participating in at least one survey semester. The return rate for forms sent to clinicians was 92% (113 out of 123 forms).
Table 1 – Distribution of the number of cases reported in metropolitan France according to case definitions | ||||||||||
|
2001 |
2002 |
2003 |
2004 |
2005 |
2006 |
2007 |
2008 |
2009 |
2010 |
Number of cases reported by laboratories (IgM+) |
164 (a) |
141 (b) |
111 |
90 |
110 |
118 |
75 |
65 |
144 |
123 |
Excluded cases |
125 |
120 |
95 |
80 |
94 |
111 |
70 |
63 |
137 |
119 |
Possible primary or reinfection |
4 |
11 |
11 |
12 |
5 |
7 |
4 |
7 |
14 |
6 |
Lost to follow-up, files not returned, no pregnancy |
17 |
9 |
1 |
3 |
9 |
26 |
4 |
31 |
47 |
23 |
Absence of pregnancy |
57 |
64 |
50 |
21 |
22 |
11 |
22 |
9 |
17 |
15 |
Rubella immunity prior to pregnancy |
38 |
35 |
32 |
42 |
55 |
65 |
40 |
16 |
52 |
69 |
Other (including vaccination during pregnancy) |
9 |
1 |
1 |
2 |
3 |
2 |
7 |
6 |
||
Confirmed and probable maternal rubella infections |
39 |
21 |
16 |
10 |
16 |
7 |
5 |
2 |
7 |
4 |
Confirmed primary infections |
27 |
14 |
11 |
4 |
11(c) |
3 |
4 |
1 |
5 |
2 |
Confirmed re-infections |
1 |
|||||||||
Confirmed infections |
1 |
2 |
1 |
|||||||
Probable primary infections |
6 |
5 |
2 |
2 |
2 |
1 |
1 |
1 |
||
Probable reinfections |
2 |
3 |
1 |
1 |
1 |
1 |
1 |
|||
Probable infections |
5 |
2 |
2 |
1 |
||||||
|
|
|
|
|
|
|
|
|
|
|
Number of congenital infections |
21 |
11 |
9 |
3 |
9 |
0 |
2 |
0 |
2 |
1 |
Congenital rubella syndrome (CRS) |
6 |
1 |
2 |
2 |
2 |
1 |
||||
Teratogenic rubella (termination of pregnancy) |
1 |
1 |
1 |
1 |
||||||
Non-teratogenic rubella infection or unknown clinical status |
14 |
9 |
6 |
1 |
7 |
2 |
1 |
|||
(a) 3 cases of possible infection reported in 2002 (b) 1 case of possible infection reported in 2003 (c) twin pregnancy
In 2010, 4 cases of confirmed and probable maternal rubella infections were recorded in mainland France, none in the overseas departments and territories. One child was born with a congenital infection and a normal clinical examination. The ratio of rubella infections during pregnancy recorded by Rénarub to the number of live births (LB) in mainland France was 0.50 per 100,000, and that of RCM was zero.
Ratio of rubella infections in pregnant women and congenital rubella syndrome cases per live births – Metropolitan France, 1976–2010
While between 2002 and 2005, the infection-to-live-birth ratio was higher among young women aged 15–19 (13.1 to 20.1 cases per 100,000 LB depending on the year), this ratio has been zero for this age group since 2008.
Table 2 - Age distribution of pregnant women infected with rubella, mainland France, 2002–2010 | ||||||||||||
Number of cases |
Rate of infections per 100,000 live births* |
|||||||||||
Age groups |
Average 2002–2005 |
2006 |
2007 |
2008 |
2009 |
2010 |
Average 2002–2005 |
2006 |
2007 |
2008 |
2009 |
2010 |
15–19 years |
2.3 |
1 |
15.1 |
0.0 |
6.8 |
0.0 |
0.0 |
0.0 |
||||
20–24 years |
6.8 |
3 |
3 |
1 |
6.6 |
2.8 |
2.9 |
0.0 |
0.0 |
01.0 |
||
25–29 years |
2.3 |
1 |
1 |
3 |
1 |
0.9 |
0.4 |
0.0 |
0.4 |
1.2 |
0.4 |
|
30–34 years |
2.3 |
2 |
1 |
2 |
1 |
0.9 |
0.8 |
0.4 |
0.0 |
0.8 |
0.4 |
|
35–39 years |
0.8 |
1 |
1 |
0.7 |
0.8 |
0.0 |
0.0 |
0.7 |
0.0 |
|||
40–44 years |
0.5 |
1 |
1 |
1 |
1.8 |
0.0 |
0.0 |
3.2 |
3.1 |
3.1 |
||
Total |
14.8 |
7 |
5 |
2 |
7 |
4 |
1.9 |
0.9 |
0.6 |
0.1 |
0.9 |
0.5 |
* LB=live births
Trends in the number of maternal infections leading to medical terminations of pregnancy or the birth of children with congenital rubella syndrome – 1997 to 2010
Discussion / Conclusion
The number of rubella infections diagnosed during pregnancy and recorded by the Rénarub network has been declining since 2001 and has been below 10 cases per year since 2006, with a maternal infection-to-live-birth ratio of less than 1/100,000.
One congenital infection was diagnosed in 2010, and no newborns were affected by congenital rubella syndrome. Since 2006, the number of CRS cases has remained below 2 per year.
It should also be noted that since 2006, the number of pregnancies terminated due to maternal infection has been fewer than 5 and was 2 in 2010.
These data suggest very low residual circulation of the rubella virus and may reflect improved catch-up vaccination among non-immune adolescent girls and young women.
An underestimation of the actual number of maternal infections is possible within the Rénarub network, which may be primarily due to a failure to diagnose in pregnant women, as rubella infections are frequently asymptomatic or atypical. The active participation, since the creation of Rénarub, of specialized laboratories that receive control samples when a maternal infection is suspected suggests that even if the network is not entirely comprehensive, and even if the participation rate of all laboratories or clinicians is not 100%, the vast majority of confirmed and probable cases are captured by the surveillance system.
