Hepatitis Sentinel Surveillance

Study Results

On this page you can find a summary of the most recent annual results from the sentinel surveillance study of Hepatitis testing. More detailed information is published quarterly in the Health Protection Report, which can be found under further information.

If you are a study participant you can log in to the website using the form at the left-hand side of the page to see additional data relevant to your sentinel laboratory or local Health Protection Unit.

Quarterly results from the study are published in the Health Protection Report (HPR), as detailed in the Further information section on this site, and once per year annual results are also published in the HPR.

Annual results: January to December 2008

In 2008 test results and demographic data (age-group and sex) were collected from 20 laboratories throughout England (figure 1). This includes results from an additional London laboratory which joined the study this year.

Please note: all the results below refer to individuals not the number of samples tested.

1. Hepatitis C

Hepatitis C is also known as Hep C or HCV (Hepatitis C virus).

The virus is spread by infected blood.

The most common risk factor is sharing contaminated needles when injecting drugs.

There is no vaccination currently available for hepatitis C.

A sample of blood can be tested for antibodies to hepatitis C (anti-HCV).

The presence of anti-HCV indicates that the individual has been exposed to the virus, but does not tell us when the individual acquired their infection. Another test, called PCR, tells us whether the individual is currently infected.

Between January and December 2008, 150,775 individuals were tested at least once for hepatitis C; 3.7% tested positive. The proportion of people who tested positive varied by region. (Figure 2). The number of people tested in each region appears to vary; this is due to the nature of the sentinel surveillance study, in that in some regions we have a large number of laboratories participating in the study, in others the laboratories may be larger in size (therefore covering a larger population).The laboratories included in the study cover approximately one-third of the English population.

Figure 2. Number of individuals tested and percentage positive, for anti-HCV in participating centres, January - December 2008*

*Excludes reference and confirmatory testing. Some duplication of individual patients may occur due to limitations of the information supplied. Individuals aged less than one year are excluded since positive tests in this age group may reflect the presence of passively-acquired maternal antibody rather than true infection. All data are provisional. . Although all sentinel centres are in England, a small amount of first-line testing from general practices in Wales is carried out by laboratories in the North West and West Midlands.

Figure 3 shows the age and gender of individuals tested, and testing positive, for hepatitis C in sentinel laboratories between January and December 2008. Similar numbers of males and females were tested. Most of the people tested were aged between 15 and 44 years.

Figure 3. Age and gender of individuals tested for anti-HCV in participating centres, January - December 2008*

* Excludes reference and confirmatory testing. Individuals aged less than one year are excluded since positive tests in this age group may reflect the presence of passively-acquired maternal antibody rather than true infection. Some duplication of individual patients may occur due to limitations of the information supplied. All data are provisional.

Figure 4 shows the average number of people tested for anti-HCV and percentage positive over the 12 months of 2008 (January to December 2008 inclusive) for the 18 centres from which full data were available. Apart from a trough during both Christmas and Easter holiday periods, there was a slight increase in the number of people tested for anti-HCV up until week 36. Testing between weeks 36 to 41 showed a more marked increase which declined to previous levels by week 49. Several peaks in testing correspond to simultaneous troughs in the percentage positive; perhaps suggesting increased testing of people at low risk of infection. An overall decline in the percentage positive over the past year can be seen, in line with the long-term trend of a declining percentage positive since the study started in 2002.

Figure 4. Five-weekly moving average of number of people tested, and percentage positive, for anti-HCV between January to December 2008* (Note difference in scale of axes compared with Figures 8 and 11)

2. Hepatitis B surface antigen (HBsAg) testing

Hepatitis B is also known as hep B or HBV (hepatitis B virus).

The virus is spread when blood or body fluids from an infected person enters the bloodstream of another.

The greatest risk factors for acquiring Hepatitis B are from contaminated needles, sexual transmission, and transmission from an infected mother to her unborn child.

A vaccine is available to health care workers or those at high risk of infection, such as injecting drug users.

If an infection by hepatitis B is suspected a blood sample can be tested for hepatitis B surface antigen (HBsAg). This antigen is the most commonly tested for marker of hepatitis B.

Between January and December 2008, 245,443 individuals were tested at least once for hepatitis B. This is the first time these individuals had been reported to the sentinel surveillance scheme.

The results below are broken down into two groups: women tested antenatally and non-antenatal testing.

a) Antenatal HBsAg testing

All pregnant women in the UK are offered hepatitis B screening as part of their antenatal care. The study team identify antenatal testing by looking at the location of the sample request (i.e. from an antenatal centre) or identifying comments in the clinical information that the doctor may add to the test request form (such as .antenatal booking. or .pregnancy screening.). It is possible some women undergoing antenatal screening may not be identified (for example they were tested by their GP but it was not recorded that they were having an antenatal screen), so their results may be included as non-antenatal testing (section 2b).

Between January and December 2008, 62,031 individuals were tested at least once for HBsAg , of these 0.6% tested positive. Figure 5 shows the number of tests by region and the proportion of women that tested positive. In most regions, there was a large number of women being tested antenatally; only a small proportion of these women were positive. In a few regions, for example East Midlands, only a small number of women were tested antenatally. This is due to the way antenatal samples are tested in that region . In the East Midlands samples taken for antenatal testing were sent (under contract) to NHS Blood and Transplant; therefore the testing recorded in this study reflect testing of a follow-up or additional sample

Figure 5. Number of individuals tested and percentage positive, for HBsAg through antenatal testing in participating centres, January - December 2008*

Excludes reference and confirmatory testing. Some duplication of individual patients may occur due to limitations of the information supplied. All data are provisional.

b) Non-antenatal HBsAg testing

This includes all individuals tested for HBsAg at participating centres who are not identified from the test request location or the clinical details accompanying the test request as undergoing antenatal screening.

Between January and December 2008, a total of 183,412 individuals were tested for HBsAg (excluding antenatal testing). Of these 3,384 (1.8%) were positive.

Figure 6 below shows the number of individuals tested and percentage positive, for HBsAg, by region during 2008. The percentage of individuals testing positive will vary depending on the way in which testing is targeted and/or the prevalence of the infection in the region. A relatively high percentage positive may reflect a more targeted approach to testing in by clinicians in the region.

Figure 6. Number of individuals tested, and testing positive, for HBsAg in participating centres, January - December 2008* (excluding antenatal testing).

* Excludes reference and confirmatory testing. Some duplication of individual patients may occur due to limitations of the information supplied. All data are provisional. . Although all sentinel centres are in England, a small amount of first-line testing from general practices in Wales is carried out by laboratories in the North West and West Midlands.

Figure 7 shows the age and gender of individuals tested, and testing positive, for HBsAg in sentinel laboratories between January and December 2008. Similar numbers of males and females were tested. The highest percentage of individuals testing positive was among those aged 35-54 years, at 2.3%.

Figure 7. Age and gender of individuals tested for HBsAg in participating centres, January . December 2008 (excluding antenatal testing)*

* Excludes reference and confirmatory testing. Some duplication of individual patients may occur due to limitations of the information supplied. All data are provisional.

Figure 8 shows the average for number of people tested for HBsAg and percentage positive during the 12 months of 2008 (excluding antenatal testing; January to December 2008 inclusive) for the 18 centres from which full data were available. There was little variation in the number of individuals tested, apart from troughs during the Easter and Christmas holiday periods and a peak around week 41. There was a slight decrease in the proportion of individuals testing positive for HBsAg during 2008.

Figure 8. Five-weekly moving average of number of people tested, and percentage positive, for HBsAg between January 2008 and December 2008* (excluding antenatal testing)(Note difference in scale of axes compared with Figures 4 and 11)

* Excludes reference and confirmatory testing. Some duplication of individual patients may occur due to limitations of the information supplied. All data are provisional.

3. Hepatitis A IgM testing

Hepatitis A is also known as hep A or HAV (hepatitis A virus).

The virus is usually spread through contact with infected waste (faecal-oral route) or occasionally through infected blood.

Better hygiene and safe drinking water have decreased the incidence of infection in the UK throughout the 21st Century.

Vaccination is available to individuals at high risk of infection, such as travelers to countries where hepatitis A is common.

If a recent infection by hepatitis A is suspected a blood sample can be tested for anti-HAV IgM. This is a specific antibody produced by the immune system in the presence of an acute hepatitis A infection.

Between January and December 2008, 27,163 individuals were tested at least once for hepatitis A; 0.6% were positive. This is the first time these individuals had been reported to the sentinel surveillance scheme.

Figure 9 below shows the number of individuals tested and percentage positive, for hepatitis A, by region from during 2008.Overall, only a small proportion of people tested for hepatitis A are positive.

Figure 9. Number of individuals tested, and testing positive, for anti-HAV IgM in participating centres, January - December 2008*

*Excludes reference and confirmatory testing. Some duplication of individual patients may occur due to limitations of the information supplied. All data are provisional. Although all sentinel centres are in England, a small amount of first-line testing from general practices in Wales is carried out by laboratories in the North West and West Midlands.

Figure 10. shows the age and gender of individuals tested, and testing positive, for Hepatitis A in sentinel laboratories January to December 2008. Gender was reported for the majority of people tested; with slightly more males than females tested. The highest percentage of individuals testing positive was among those aged 45-55 years 6.2%.

Figure 10. Age and gender of individuals tested for anti-HCV in participating centres, January - December 2008*

*Excludes reference and confirmatory testing. Some duplication of individual patients may occur due to limitations of the information supplied. All data are provisional.

Figure 11. shows the average number of people tested for hepatitis A and percentage positive over the 12 months of 2008 (January to December 2008 inclusive) for the 18 centres from which full data were available. There was little variation in the number of individuals tested, apart troughs during the Christmas, Easter, and summer holiday periods with small peaks shortly after. The proportion of people testing positive increased between weeks 34 to 43 and then decreased again.

Figure 11. Five-weekly moving average of number of people tested, and percentage positive, for anti-HAV IgM between January to December 2008* (Note difference in scale of axes compared with Figures 4 and 8)