• Confirmed measles cases in England and Wales – an update to the end of October 2008

• The fourth year of the Department of Health's mandatory surveillance of surgical site infection in orthopaedic surgery in NHS hospitals in England

• Eye of the Needle: surveillance of significant occupational exposures to bloodborne viruses in healthcare workers, 2000-2007

• NHSBT/HPA Infection Surveillance Programme annual report, 2007

Confirmed measles cases in England and Wales - an update to the end of October 2008

This article describes measles activity in October 2008 in England and Wales; routine data on laboratory confirmed measles, mumps and rubella for the third quarter of 2008 are summarised in the Infection Reports section of this issue [1].

In October, 83 cases of measles were confirmed in England and Wales (see figure 1), marginally higher than the previous month (72 cases), and attributable to an increase in reports from outside London. The number of cases in London remained similar to the number reported in September (table). The number of laboratory confirmed cases since the start of the year is now 1049, exceeding the total of 990 for the whole of last year. During October, 9% of oral fluid tests on notified cases of measles were positive, however, in London 15% of all samples tested were confirmed whereas in the rest of England and Wales the proportion was 7%.

Figure 1: Number of laboratory confirmed cases in England and Wales by month of onset: January 2007 to October 2008

The North West region reported further 11 cases linked to outbreaks in schools in Cheshire [2]. Outbreaks in Wales, South East, East and West Midlands reported previously are continuing [3]. The number of confirmed cases in London remained constant for the third consecutive month with cases reported from all four Health Protection Units in London. A small outbreak was investigated in patients from the Polish community in London.

Both D4 (MVs/Enfield/14.07 and MVs/Chester/38.08) are continuing to circulate in different parts of England and Wales.

Over 50% of all confirmed cases this year have occurred in children of nursery and primary school age (figure 2).

Table Confirmed cases of measles by region and month of onset, England and Wales: January 2008 to October 2008

Month	Lond-on	East Mids	East of Engl'd	North East	North West	South East	South West	West Mids	Wales	York & Humber
Jan	60	1	8	1	1	1	–	3	1	11
Feb	44	–	4	3	–	7	–	–	–	3
Mar	67	1	1	–	–	6	1	1	1	5
Apr	94	–	8	3	1	6	15	2	–	15
May	103	1	6	–	23	4	7	3	–	4
Jun	100	–	10	1	22	7	3	5	–	3
Jul	68	1	10	–	22	17	3	8	–	2
Aug	31	8	8	–	14	17	–	6	–	2
Sep	29	3	3	–	7	3	–	7	20	–
Oct*	30	8	4	1	16	8	–	5	10	–
Total	626	23	62	9	106	76	29	40	32	45

*Does not include one sample with unknown region

Figure 2: Confirmed cases by age groups targeted by the MMR catch-up programme, England and Wales: January 2008 to October 2008

References
1. Laboratory confirmed cases of measles, mumps and rubella, England and Wales: July to September 2008. Health Protection Report [serial online] 2008, 2(48): immunisation (Infection Reports section of this issue).

2. Fears rise over measles outbreak. BBC Website [online] Wednesday, 29 October 2008. http://news.bbc.co.uk/1/hi/england/manchester/7697269.stm.

3. HPA. Confirmed measles cases in England and Wales - an update to September Health Protection Report [serial online] 2008 [cited 7 November 2008]; 2(45): news. Available at: http://www.hpa.org.uk/hpr/archives/2008/news4508.htm#msls0809.

The fourth year of the Department of Health's mandatory surveillance of surgical site infection in orthopaedic surgery in NHS hospitals in England

The surveillance of surgical site infections (SSI) began in 1997 for 13 surgical categories, four of which are orthopaedic categories: hip prosthesis, knee prosthesis, open reduction of long bone fracture and hip hemiarthroplasty. The surveillance of SSIs in the four orthopaedic categories became mandatory in England from 1 April 2004 [1]. This was in response to the action plan on healthcare associated infections in the Chief Medical Officer's strategy to combat infectious diseases, Getting ahead of the Curve [2].

The fourth report of the mandatory surveillance of SSI has been published on the Health Protection Agency's website on: http://www.hpa.org.uk/webw/HPAweb&Page&HPAwebAutoListName/Page/1191942150156?
p=1191942150156

This report presents data on the participation of hospital Trusts in the surveillance, the incidence of surgical site infection (SSI) by each of the four categories of procedure, differences between the first year (2004-05) and the fourth year (2007-08), the incidence by risk groups and summary data on the most common causative micro-organisms recovered from surgical site infections.

The key points of the report are:

• Data on 69,200 procedures were collected from 155 participating Trusts including six independent NHS treatment centres during the fourth year of mandatory surveillance of surgical site infection (2007/08). This represented almost 8,000 more procedures than the previous year (2006/07).
• Most Trusts have been undertaking surveillance in hip and knee replacement categories.
• Participation is mandatory for at least one three-month surveillance period; 40% of Trusts undertook continuous surveillance throughout the fourth year in at least one category of orthopaedic procedure.
• There was a significant decrease in the rate of SSI between the first (2004/05) and fourth year (2007/08) of the mandatory surveillance in each of the four categories. In 2007/08, the proportion of operations that resulted in SSIs was 0.5%, 0.3%, 2.4% and 0.9% for hip prosthesis, knee prosthesis, open reduction of long bone fracture and hip hemiarthroplasty, respectively.
• In most NHS Trusts the rates of SSI in orthopaedic surgery were low.
• The rate of SSI increases as the Risk Index score increases. (The Risk Index measures the presence of up to three risk factors in each patient: pre-operative health score of three or more (indicating severe underlying condition), duration of operation above the 75th percentile and a surgical wound class that is contaminated or dirty).
• The rate of SSI is highest in the hip hemiarthroplasty category. This is partly explained by the fact that this category comprises an older group of patients (median age is 84 years compared to 70 to 75 years in the other categories). Older patients are more likely to have a longer post-operative stay in hospital thus increasing the chance that SSIs will be detected during the inpatient stay.
• Most of the SSIs reported affected the superficial layers of the wound, but approximately a quarter involved the deeper tissues.
• Staphylococcus aureus is recognised as a major cause of SSIs and over the four years of the mandatory surveillance, it accounted for 44% of all surgical site infections. Of all SSIs caused by S. aureus, 60% were methicillin-resistant (MRSA). Just over a quarter of all SSIs (26%) were caused by MRSA.
• Only four Trusts had higher than expected rates of infection in the fourth year, and none were found to be a high outlier in more than one surgical category. These Trusts are investigating possible causes for their higher rates.
• The length of post-operative stay in hospital decreased from seven days in 2004/05 to five days in 2007/08 for both hip and knee prosthesis surgery. In hip hemiarthroplasty the median length of post-operative stay has reduced by one day to 13 days. The decreasing length of post-operative stay means that the surveillance based on SSIs detected in inpatients is increasingly likely to underestimate the true rate of SSI, affecting the interpretation of changes in rates over time.

Other data presented are SSI rates by Trust and year: http://www.hpa.org.uk/webw/HPAweb&Page&HPAwebAutoListName/
Page/1191942150156?p=1191942150156

The rates at Trust level should be interpreted with caution as some represent estimates based on small numbers of orthopaedic procedures and are therefore imprecise. The number of procedures on which rates are based varies according to the throughput of the given type of surgical procedure at the Trust and the number of surveillance periods they have chosen to participate in.

The possibility that an SSI will be detected depends on the length of time that the patient spends in hospital post-operatively.  Some of the variation in rates may therefore be explained by differences in length of post-operative follow-up.  In addition, the rates included in these tables have not been adjusted for underlying risk factors related to the patient or their operation that could affect the risk of developing an SSI, for example age, underlying illness, complexity of the operation. 

References

1. HPA. Mandatory surveillance of surgical site infections in orthopaedic surgery. Commun Dis Rep CDR Weekly [serial online] 2004 [cited 1 April 2004]; 14(4): news. Available at: http://www.hpa.org.uk/cdr/archives/2004/cdr0404.pdf.

2. Department of Health (Chief Medical Officer). Getting ahead of the curve: a strategy for combating infectious diseases (including other aspects of health protection). London: Department of Health, 2002. Available at:http://www.dh.gov.uk/assetRoot/04/06/08/75/04060875.pdf.

Eye of the Needle: surveillance of significant occupational exposures to bloodborne viruses
in healthcare workers, 2000-2007

The 2008 Eye of the Needle report – surveying the extent of healthcare worker exposure to patients with hepatits B, hepatitis C or HIV infections in England, Wales and Northern Ireland between 2000-2007 – has been published by the Health Protection Agency Centre for Infections [1].

A key finding of the report is that healthcare workers (HCW) exposed to hepatitis C positive source patients, in particular, are not routinely receiving follow-up testing in line with national guidance [2] – highlighting the need for greate awareness among healthcare workers of the importance of attending follow-up appointments to ensure they know the outcome of their exposure. Only 22% (40/184) of healthcare workers exposed to a hepatitis C positive source patient returned for the appropriate follow-up tests at the correct time points in 2007. This finding is of concern since the majority of hepatitis C infected cases show no symptoms of their infection. It can take up to 30 years before the symptoms of infection manifest, by which time chronic damage to the liver has already occurred. Microbiologists and virologists working with occupational health, infectious disease and GUM specialists are encouraged to ensure that appropriate and timely testing and follow-up arrangements are available and are consistent with national guidance.

In 2006-2007 there were four documented patient-to-healthcare worker hepatitis C transmissions following percutaneous exposure. This brings the total number of hepatitis C seroconversions in healthcare workers reported between 1997 and 2007 to 14 cases in England, with an additional case notified in Scotland in 2007. Fourteen healthcare workers have cleared the virus, with the 10 healthcare workers who were known to have started treatment achieving a sustained virological response. One healthcare worker is still undergoing treatment.

Encouragingly the report found that 78% of healthcare workers significantly exposed to an HIV-positive source patient did start HIV post-exposure prophylaxis (PEP) in 2007; also that the national guidance on the use of HIV PEP was followed in the majority of cases. It is recommended that HIV PEP should be started as soon as possible after such exposures, ideally within an hour, as detailed in guidelines from the Expert Advisory Group on AIDS [3]. Thirty-seven per cent of healthcare workers exposed to HIV who initiated HIV PEP did so within an hour of their exposure and 89% within 24 hours. Since 1999, there have been no new reported cases of HIV seroconversions following percutaneous exposures of healthcare workers to HIV positive source patients. This brings the total number of UK HIV documented seroconversions reported by 2007 to five.

A further 914 incidents were reported to the surveillance scheme between 2006 and 2007. The most commonly reported occupational exposures in the healthcare setting were perrcutaneous injuries involving hollowbore needles (68%), with a large proportion of percutaneous exposures involving hepatitis C positive source patients (48%). In 2007, for the first time, a higher number of occupational exposures were reported from medical professionals (doctors and dentists) than nursing professionals (200 compared to 191). This suggests that medical professionals reported to the scheme have a higher injury rate, as doctors and dentists are a much smaller group of healthcare workers compared to nursing professionals.

Over a third of incidents in the ward or in Accident and Emergency (43% and 37% respectively), and around 20% in intensive care and in operating theatres (22% and 20% respectively), occurred after the procedure had taken place. Many of these incidents could have been prevented with proper adherence to the safe handling and disposal of sharps and clinical waste. There is guidance in place that details the recommended procedures for the prevention of exposure to bloodborne viruses in the healthcare setting [4] and Trusts should ensure that healthcare workers are aware and adequately trained on the implementation in these precautions in order to protect themselves from exposures. Employers should also have adequate systems for reporting and management of occupational exposures in operation 24 hours a day, seven days a week, and should ensure that all staff members know how to report such incidents, in line with current guidance [3, 5].

Centres participating in the surveillance scheme were audited in 2007 to examine the provision of occupational health services to community-based healthcare workers. Initial analyses indicate that, where information was given, the majority of participating centres do provide services to community-based healthcare workers, although there were problems with the reporting of exposures by staff, due to lack of knowledge of protocols and logistics. Primary Care Trusts working with local Health Protection Units should ensure that arrangements are in place for managing occupational exposures to healthcare workers occurring outside the hospital environment.

To report incidents of healthcare workers occupationally exposed to bloodborne viruses in England, Wales and Northern Ireland, please contact Sarah Tomkins /Dr Susan Cliffe at the Centre for Infections (tel: 020 8327 7095/7152).

References
1. Health Protection Agency Centre for Infections, National Public Health Service for Wales, CDSC Northern Ireland and Health Protection Scotland. Eye of the Needle. United Kingdom surveillance of significant occupational exposures to bloodborne viruses in healthcare workers. November 2008. Available at: www.hpa.org.uk/needle.

2.Ramsay ME. Guidance on the investigation and management of occupational exposure to hepatitis C. Commun Dis Public Health 1999; 2: 258-62.

3.Department of Health. HIV post-exposure prophylaxis: guidance from the UK Chief Medical Officers' Expert Advisory Group on AIDS. London: Department of Health, September 2008.

4. Expert Advisory Group on AIDS and the Advisory Group on Hepatitis. Guidance for clinical health care workers: protection against infection with bloodborne viruses. London: UK Health Departments; 1998.

5. Department of Health. The Health Act 2006: Code of Practice for the Prevention and Control of Healthcare Associated Infections. London: Department of Health, January 2008.

NHSBT/HPA Infection Surveillance Programme annual report, 2007

The fourth annual report from NHS Blood and Transplant (NHSBT)/Health Protection Agency (HPA) Centre for Infections Surveillance Programme is now available at: http://www.hpa.org.uk/infections/topics_az/BIBD/publications.htm.

The programme is comprised of a series of national schemes, which provide epidemiological information about bloodborne infections in blood, tissue and cell donors in the UK and the associated risk of transmission via transfusion or transplantation, in order to inform donor practices and public health. In addition, information about antenatal samples tested by the NHSBT is presented. This report includes national data from all the schemes within the NHSBT/HPA programme, and aims further to describe the methods used and the information collected; describing any trends observed and detailing some of the applications of the data including the estimated risks of the current donation testing strategies not identifying an infectious donation.

Key information in the report includes:

• A continuing increase was seen in the frequency of HIV among male repeat blood donors; the frequency of HIV in repeat donors was low, but by 2007 it was higher than hepatitis B or C viruses.
• Hepatitis C was the only infection where the frequency continued to decline in both new and repeat blood donors.
• Rubella susceptibility increased by 0.5% in 2007 to 2.5% of samples from antenatal women.
• During 2007, 5/545 deceased donors were confirmed positive (4 syphilis and 1 HCV), the highest number of infections detected in this donor group since surveillance began in 2001.
• In 2007, there were no confirmed transmissions of viruses via transfusion of blood components but two confirmed bacterial transmissions from red cells units; the first time transmission from red cells have been reported since the SHOT report year 2001/2002.
• Data on residual risk estimates for the English surgical bone donor population was included for the first time using recently published methods [1].

In addition to this annual report, some of these data are routinely published on the HPA website [2] and in the Health Protection Report, and data from the transfusion transmitted infection surveillance scheme form a part of SHOT (Serious Hazards of Transfusion) website http://www.shotuk.org.

References
1. Brant LJ, Davison KL. Infections detected in English surgical bone and deceased donors (2001-2006) and estimated risk of undetected hepatitis B and hepatitis C virus. Vox Sang 2008; 95, 272-279.
2. www.hpa.org.uk/infections/topics_az/BIBD/publications.htm.