Research and analysis

HPR volume 8 issue 47: news

Updated 23 December 2014

1. Laboratory confirmed pertussis in England: data to end-October 2014

This news report presents current pertussis activity to 31 October 2014, updating the previous report that included data to the end of August 2014 [1].

Overall pertussis activity in England in 2014 persists at raised levels compared to the years preceding the national outbreak declared in 2012* [2]. Expected seasonal increases were observed in August and September with confirmed cases falling in October.

The pertussis vaccination in pregnancy programme was introduced in October 2012 to protect infants in their first few weeks of life. Confirmed pertussis cases in infants less than 6 months of age have remained low despite the continued high activity in other age groups. The immunisation programme for pregnant women continues to be important, particularly in light of the ongoing raised levels of pertussis in those from 1 year of age and recent infant deaths. There have been recent key publications on the high effectiveness and safety of the programme [3,4,5].

Available data relating to the coverage, effectiveness and safety of the immunisation programme for pregnant women, its impact on disease and current epidemiology were considered by the Joint Committee on Vaccination and Immunisation (JCVI) in June 2014 and the committee advised that the programme should be continued for at least a further five years [6].

In infants under 3 months of age low numbers of cases have been sustained since December 2012 with fewer than 10 cases per month reported up to August 2013 and six or fewer reported each month between September 2013 and March 2014. Cases increased from April 2014, in line with expected seasonal increases, peaking at 21 cases in July 2014; the highest number of monthly cases since 23 reported in November 2012. The number of cases aged under 3 months and aged between 6 and 11 months confirmed between January and October 2014 exceeds the total number reported in 2013 for these age groups. The greatest reduction in disease since the peak in 2012 has, however, been in infants under 6 months of age. Disease incidence has, as expected, continued to be highest in this age group but case reports are now in line with those seen before the 2012 peak. There have been 7 deaths reported in young babies (under 10 weeks) diagnosed with pertussis this year. Ten deaths have been reported in young babies with confirmed pertussis who were born after the introduction of the pregnancy programme on 1 October 2012. Nine of these 10 babies were born to mothers who had not been vaccinated against pertussis, all of the 10 babies were too young to be fully protected by vaccination themselves and none had received their first dose of pertussis-containing vaccine.

Pertussis activity in infants aged 6 to 11 months and 1 to 4 years of age remained low but confirmed cases were higher to the end of October 2014 than the equivalent period in the previous six years, other than the peak in 2012. Whilst small numbers of cases were confirmed in those aged 5 to 9 years, these increased slightly from February 2014 and in the first 10 months of 2014 exceeded the total in 2013. Cases in this age group persist at levels notably higher than those confirmed prior to 2012.

Pertussis activity in adolescents, teenagers and adults (aged from 10 years) continued to decrease overall** with a small seasonal peak into August and September 2014. Overall, confirmed cases of pertussis were lower between January and October 2014 than in the first 10 months of the 2 preceding years but cases continued to exceed those confirmed in years prior to 2012. This pertussis activity has been observed across all regions in England with relatively high numbers of cases in 2014 reported from Yorkshire and Humber and from Surrey, Sussex and Kent**.

The pertussis vaccination in pregnancy programme continues to be important for the prevention of serious disease and death in young babies. To optimise protection of their babies, women should ideally be immunised between 28 and 32 weeks gestation but may be immunised up to week 38 of pregnancy. Pregnant women who remain unprotected can be offered vaccination after 38 weeks as can new mothers who have not been vaccinated in pregnancy. Vaccination at this stage is not ideal, however, as it would potentially only directly protect the mother against disease and thereby just reduce the risk of exposure to her infant.

The latest vaccine uptake report for April to August 2014 estimates that approximately 54% of all pregnant women in England are currently being vaccinated in pregnancy [7]. This is important because around 75% of all cases of pertussis in babies occur before they can be protected by even the first dose of infant vaccine and when there is a high risk of serious disease. The babies that have died from pertussis in England over recent years all acquired pertussis in the first few weeks of life and 9 of the 10 babies who died between January 2013 and October 2014 were born to mothers who were not vaccinated during pregnancy. Information generated from the pertussis immunisation in pregnancy programme in England has shown high levels of protection against disease in babies born to vaccinated women. Babies born to women vaccinated at least a week before delivery had a reduction in the risk of disease in their first weeks of life of greater than 90% when compared to babies whose mothers had not been vaccinated [3,5]. In addition, no safety concerns were found relating to pertussis vaccination in pregnancy in a study undertaken by the Medicines and Healthcare Products Regulatory Agency [4].

* See figure in the PDF version of this issue of HPR.

** See tables in the PDF version of this issue of HPR.

1.1 References

1. Confirmed pertussis cases in England and Wales: update to end-August 2014. HPR 8(38): news, 3 October 2014.

2. The outbreak was declared in April 2012 in response to ongoing increased pertussis activity. See HPR 6(15).

3. Amirthalingam G, Andrews N, Campbell H et al. Effectiveness of maternal pertussis vaccination in England: an observational study, Lancet 2014.

4. Donegan K, King B, Bryan P. Safety of pertussis vaccination in pregnant women in the UK: observational study, BMJ 2014.

5. Dabrera G, Amirthalingam G, Andrews N et al (2014). A Case-Control Study to Estimate the Effectiveness of Maternal Pertussis Vaccination in Protecting Newborn Infants in England and Wales, 2012–2013. Clinical Infectious Diseases (online), 19 October.

6. Joint Committee on Vaccination and Immunisation minutes.

7. Pertussis Vaccination Programme for Pregnant Women: vaccine coverage estimates in England, October 2012 to March 2014 (PHE statistics).

2. Surgical site infection surveillance in NHS hospitals in England, 2013/14

A report summarising data collected by 235 NHS hospitals and independent NHS Treatment centres in England between April 2009 and March 2014, as part of the PHE surveillance of surgical site infections (SSI) programme, has been published on the GOV.UK website [1].

The report presents the rate of SSIs for 17 categories of surgical procedures based on infections detected during the patient’s post-operative stay (inpatient SSIs) combined with infections detected on re-admission after initial discharge (readmission SSIs). Readmission surveillance became a requirement from July 2008; prior to this readmission cases were collected on a voluntary basis.

NHS Trusts in England performing orthopaedic surgery in one of the 4 mandatory surveillance categories (hip prosthesis, knee prosthesis, reduction of long bone fracture and repair of neck of femur) are required to undertake SSI surveillance in at least one of these surgical categories for a minimum of one quarter per financial year. NHS Trusts also have the option of participating in any of the additional 13 surgical categories included in the national surveillance scheme.

Surveillance of surgical site infections is undertaken by hospitals in England using standard definitions for infections that affect the superficial incisional site, the deeper layers or those involving the joint or organ-space as outlined in the surveillance protocol [2]. Patients are systematically, prospectively followed-up to identify infections occurring within 30 days of surgery or within one year if a prosthetic implant is used. Surveillance of SSI outcome is now complemented by measurement of process indicators as outlined in the NICE SSI quality standards [3]. This tool provides an effective means to monitor the quality of patient care based on seven standards.

The report describes hospital participation in surveillance over time, data quality indicators, trends and risk factors for SSI. An accompanying supplement lists orthopaedic SSI rates by named NHS Trust, also available in due course from the NHS Choices website.

Key findings are:

• data on 594,855 surgical procedures and 8,458 inpatient/readmission SSIs, from 17 surgical categories, were collected by 234 NHS hospitals and independent sector NHS treatment centres in the five-year period between 2009/10 and 2013/14

• in 2013/14, 143 NHS Trusts and an additional 8 NHS Treatment centres participated in the mandatory orthopaedic surveillance, contributing data on 102,570 procedures. One eligible NHS Trust did not participate. Of those that participated, 10 NHS Trusts were identified as high outliers with an incidence of SSI higher than expected nationally. An additional 7 were identified as low outliers. All 17 NHS Trusts have been contacted and encouraged to review their clinical and surveillance practices

• between 2008/9 and 2013/14, a significant decrease in the inpatient/readmission SSI incidence was found for repair of neck of femur and reduction of long bone fracture, reaching 1% in each category in 2013/14. No trends in SSI for hip and knee prosthesis were found with the incidence remaining low (<1%) in these categories

• Analysis of hospital-level trends for the orthopaedic categories showed that the majority of centres exhibited stable or decreasing trends over time

• among non-orthopaedic categories, a significant increasing trend in SSI was found for spinal surgery with an SSI rate of 1.3% in 2013/14. A significantly decreasing trend in was found for patients undergoing bile duct/liver/pancreatic and gastric surgery

• Staphylococcus Aureus as a reported cause of inpatient SSIs accounted for 16% of cases in 2013/14. This followed a decreasing trend from 2006/07 due to decreases in methicillin-resistant Staphylococcus Aureus (MRSA). Enterobacteriaceae increased from 2008/9 and accounted for 26% of cases by 2013/14

• in 2013/14, Staphylococcus Aureus was the predominant organism in orthopaedic and spinal surgery accounting for ≥40% of cases. Coagulase-negative staphylococci and Enterobacteriaceae were predominant in coronary artery bypass graft and large bowel surgery respectively.

2.1 References

1. Surveillance of surgical site infection in NHS hospitals in England, 2013/14 (PHE, December 2014).

2. PHE (2013). Protocol for the surveillance of surgical site infection. Version 6 June 2013.

3. NICE (2103). Surgical Site Infection Quality Standards, QS49.

3. Ebola virus disease: international epidemiological summary (at 9/12/2014)

Up to the end of 9 December (7 December for Liberia), a total of 18,152 clinically compatible cases (CCC) of Ebola virus disease (EVD) have been reported in the 5 currently affected countries (Guinea, Liberia, Sierra Leone, the USA and Mali) and three previously affected countries (Nigeria, Spain and Senegal) since December 2013. There have been at least 6,548 deaths, but the true numbers are not known due to continued under-reporting. Case fatality rates remain high across Guinea, Liberia and Sierra Leone where for reported cases with a definitive outcome the case fatality rate is 76%.

The trends in national incidence continue to vary Guinea, Liberia and Sierra Leone. In Guinea, a slight increase in incidence nationally has been observed since early October. In Liberia, reported case incidence is declining nationally but hotspots of disease continue. Montserrado county, which includes the capital Monrovia, continues to report the majority of new cases. In Sierra Leone, transmission remains persistent and intense in a number of districts with the exception of the south Freetown. Freetown remains the worst affected area, reporting a third of all newly confirmed cases in the last full week of epidemiological data.

The total number of EVD CCC reported in Mali stands at eight. As of 11 December, the number of cases associated with the Bamako cluster remains at seven, five of whom have died. The two surviving cases in this cluster have tested EVD free and have been released from hospital. The situation in Bamako looks encouraging but given the porous nature of the Mali–Guinea border, the risk of further importation of cases is recognised.

To date, a total of 23 EVD cases have been cared for outside of Africa; 18 repatriated cases (hospitalised in USA, Spain, UK, Germany, France, Norway, Switzerland, Italy and the Netherlands), two imported cases (both diagnosed in USA) and three incidents of local transmission (in Spain and USA).

The table below summarises Ebola virus disease international epidemiological information as at 30 November 2014 (28 November for Liberia)

Country	Total CCCs	Total deaths	Current status
Guinea	2339	1454	Ongoing transmission
Liberia	7765	3222	Ongoing transmission
Sierra Leone	8014	1857	Ongoing transmission
Mali	8	6	Awaiting EVD free status
Nigeria	20	8	EVD free
Senegal	1	0	EVD free
Spain	1	0	EVD free
USA	4	1	Awaiting EVD free status
TOTAL	18,152	6548	–

Further information on the international epidemiological situation can be found in PHE’s weekly ebola epidemiological update.