Quarterly report from the sentinel surveillance study of hepatitis testing in England: data for July to September 2007
The sentinel surveillance study of hepatitis testing, which began in 2002, aims to supplement routine surveillance of hepatitis B and C in England by providing information on trends in testing, individual risk exposures and clinical symptoms.
The study collects information on all hepatitis B and C testing carried out in participating centres regardless of test result and therefore can also be used to estimate prevalence in those individuals tested.
It is important to note that no laboratory methods are currently available to distinguish between acute, chronic or resolved hepatitis C virus infections. Positive anti-HCV results do not therefore necessarily represent incident infections and the data presented here should be interpreted with care.
Hepatitis C virus (HCV) testing
During the third quarter of 2007, a total of 30,343 individuals were tested at least once for hepatitis C-specific antibodies (anti-HCV) in 15 participating sentinel centres (Table 1). This is the first time these individuals had been reported to the sentinel surveillance scheme.
It should be noted that data from four participating centres in the North West are not included in this report due to problems in data extraction. Figures presented in this report relating to testing in the North West region and for England as a whole are therefore not directly comparable with those from previous quarters. Work is ongoing to solve this problem and restore normal data collection in these laboratories.
Overall, 4.1% of individuals tested for anti-HCV were positive, though this varied by region (Table 1). As last quarter, the percentage of positive tests was highest in South West England: this may reflect more targeted testing of risk groups and/or genuinely higher prevalence in people being tested in this area.
Table 1. Individuals tested for anti-HCV in participating centres, July - September 2007
| Region (number of centres) | Number tested * | Number positive * (%) |
| East Midlands (1) | 1,700 | 52 (3.1) |
| Eastern (1) | 1,099 | 59 (5.4) |
| London (5) | 9,576 | 368 (3.8) |
| North East (1) | 1,249 | 25 (2.0) |
| North West (1)** | 1,210 | 92 (7.6) |
| South East (2) | 3,745 | 49 (1.3) |
| South West (1) | 3,917 | 346 (8.8) |
| West Midlands (1) | 1,239 | 53 (4.3) |
| Yorkshire and Humberside (2) | 6,608 | 208 (3.1) |
| Total, all centres (15) | 30,343 | 1,252 (4.1) |
Of the 1,252 individuals testing positive for anti-HCV during the third quarter of 2007, 736 (58.8%) were also tested for HCV RNA by PCR. Of these individuals, 474 were PCR positive (64.4%).
Sex was reported for the majority of people tested. Similar numbers of males and females were tested (table 2); the ratio of males to females tested was 1.0:1. Twice as many males were positive than females; the ratio of males to females testing positive was 2.0:1. The majority (66.6%) of people tested were aged 15-44 years. Excluding individuals aged less than one year (in whom a positive anti-HCV result does not necessarily reflect HCV infection) and those for whom age is unknown, the percentage of individuals testing positive was highest among people aged 35-54 years, for both sexes.
Table 2. Age and sex of individuals tested for anti-HCV in participating centres, July – September 2007
| Female | Male | Unknown | Total |
| Age | Number tested | Number positive (%) | Number tested | Number positive (%) | Number tested | Number positive (%) | Number tested | Number positive (%) |
| <1 | 52 | 8 (15.4) | 60 | 5 (8.3) | 4 | 1 (25.0) | 116 | 14 (12.0) |
| 1-14 | 213 | 2 (0.9) | 190 | 3 (1.6) | 14 | 0 (0.0) | 417 | 5 (1.2) |
| 15-24 | 3,072 | 46 (1.5) | 2,174 | 28 (1.3) | 175 | 1 (0.6) | 5,421 | 75 (1.4) |
| 25-34 | 4,050 | 111 (2.7) | 4,043 | 217 (5.4) | 331 | 10 (3.0) | 8,424 | 338 (4.0) |
| 35-44 | 2,731 | 103 (3.8) | 3,417 | 303 (8.9) | 196 | 7 (3.6) | 6,344 | 413 (6.5) |
| 45-54 | 1,476 | 79 (5.4) | 1,913 | 159 (8.3) | 131 | 7 (5.3) | 3,520 | 245 (7.0) |
| 55-64 | 1,161 | 36 (3.1) | 1,356 | 72 (5.3) | 94 | 0 (0.0) | 2,611 | 108 (4.1) |
| 65 plus | 1,569 | 23 (1.5) | 1,655 | 27 (1.6) | 130 | 1 (0.8) | 3,354 | 51 (1.5) |
| Unknown | 31 | 0 (0.0) | 37 | 2 (5.4) | 68 | 1 (1.5) | 136 | 3 (2.2) |
| TOTAL | 14,355 | 408 (2.8) | 14,845 | 816 (5.5) | 1143 | 28 (2.4) | 30,343 | 1,252 (4.1) |
To provide an indication of trends in testing, data from the 15 sentinel centres from which full data were available were compared for the third quarters of 2006 and 2007. In the period July to September 2007, 1,252 of 30,343 (4.1%) people tested were positive for anti-HCV, compared to 1,394 of 27,804 (5.0%) for the same period in 2006.
Please note that these data relate to different sentinel centres to those for whom trends data were presented in the last quarterly report and therefore comparisons should not be made between reports. However, Figure 1 shows the five-weekly moving average for number of people tested for anti-HCV and percentage positive over the last year (October 2006 to September 2007) for the 15 centres from which full data were available.
A slight overall increase in anti-HCV testing can be observed over the course of the year. The decrease in number of people tested between week 50 2006 and week 2 2007 corresponds to the Christmas and New Year holiday period; a slight drop is also apparent around week 34, which may correspond to the August holidays. The reasons for the two peaks that can be observed in the percentage positive are currently unknown, and work to investigate these patterns further is underway.
Figure 1. Five-weekly moving average of number of people tested, and percentage positive, for anti-HCV between October 2006 and September 2007*.
