Research and analysis

HPR volume 10 issue 23: news (15 July)

Updated 16 December 2016

1. Laboratory confirmed pertussis in England: data to end-May 2016

This report presents current pertussis activity to 31 May 2016, updating the previous report that included data to the end of March 2016 [1].

1.1 Background

In England the total number of laboratory confirmed cases of pertussis has fallen each consecutive year from a peak of 9367 cases in 2012; by 51% between 2012 and 2013 (4621 cases) and 27% between 2013 and 2014 (3387 cases). The number of confirmed cases reported in 2015 was 24% higher than in 2014 but remained lower than 2012 and 2013*. Cases of pertussis have continued to increase in the first five months of 2016.

The pertussis vaccination in pregnancy programme was introduced in October 2012 [2,3] in response to a national outbreak and a significant increase in infant cases and deaths. Evaluation of the pertussis immunisation in pregnancy programme has demonstrated the safety and high effectiveness of the programme [4,5,6]. Together with coverage and epidemiological data, these findings informed the Joint Committee on Vaccination and Immunisation’s (JCVI) decision in July 2014 that the pregnancy programme should continue for at least a further five years [7]. From 1 April 2016 the recommended gestational age for vaccination was revised to between 16-32 weeks (previously recommended from 28-32 weeks) to offer more opportunities for women to be vaccinated. For operational reasons, pertussis vaccination should be offered from around 20 weeks on, or after the foetal anomaly scan [7]. Pertussis vaccine coverage in pregnant women increased from 59.7% in January 2016 to 60.7% in March 2016. Coverage was 4.4% higher in March 2016 compared to March 2015, and 2016 is the first year of the programme where coverage has not declined during the first quarter [8].

1.2 Confirmed cases in January-May 2016

From January to May 2016, 2201 laboratory confirmed cases were reported across all ages to the enhanced surveillance programme in England compared to 1362 in the same period in 2015. Total cases for the first five months of the year were higher in 2016 than for the same period each year since 2011 with the exception of 2413 cases in 2013*. Overall pertussis activity in England persists at raised levels compared to the years preceding the outbreak in 2012**.

Pertussis activity in all infants under one year of age was low in the first five months of 2016*, with 91 cases, but higher than the equivalent periods in each of the last three years (56, 47, 46 cases in 2013, 2014, 2015 respectively). Disease incidence, as expected, continued to be highest in infants less than three months but cases were lower in January-May 2016 than during the equivalent period in the 2012 peak year and remain in line with that seen in the years before the outbreak began. There have been two deaths in infants with pertussis confirmed in the first five months of this year. Sixteen deaths have therefore now been reported in young babies with confirmed pertussis who were born after the introduction of the pregnancy programme on 1 October 2012, as at end May 2016. Fourteen of these 16 babies were born to mothers who had not been vaccinated against pertussis, all of the 16 babies were too young to be fully protected by vaccination themselves and only one had received their first dose of pertussis-containing vaccine.

The numbers of laboratory confirmed cases in those aged one year and older continued to be higher than those reported before the 2012 outbreak. Pertussis cases in those aged 10 years and older were higher in the first five months of 2016 than the totals confirmed in 2014 and 2015. In those aged 1-9 years however cases to end May 2016 (37 aged 1-4 years and 133 aged 5-9 years) were higher than those confirmed to the same point in any previous year including 2012*.

1.3 Overall trends as at end-May 2016

Overall pertussis activity was relatively high in the first five months of 2016 in all regions of the country and in all age groups, in particular in children aged 1-9 years. Whilst cases in infants less than six months have increased in January to May 2016, the numbers still remain low despite the continued high activity in older age groups*. The immunisation programme for pregnant women continues to be important, particularly in light of the ongoing raised levels of pertussis in those over one year of age and recent infant deaths.

1.4 PHE guidelines

Revised Guidelines for the Public Health Management of Pertussis in England are now available on the PHE website [9].

* See table in the PDF version of this report.

** See table and figure in the PDF version of this report.

1.5 References

1. Laboratory confirmed pertussis in England: January to March 2016. HPR 10(21): news (1 July 2016).
2. “Pregnant women to be offered whooping cough vaccination”, 28 September 2012. Department of Health website.
3. “HPA welcomes introduction of whooping cough vaccination for pregnant women as outbreak continues” HPA press release, 28 September 2012.
4. Amirthalingam G, Andrews N, Campbell H et al (2014). Effectiveness of maternal pertussis vaccination in England: an observational study Lancet.
5. Donegan K, King B, Bryan P (2014). Safety of pertussis vaccination in pregnant women in the UK: observational study British Medical Journal.
6. 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.
7. JCVI minutes.
8. Pertussis Vaccination Programme for Pregnant Women: vaccine coverage estimates in England (PHE statistics).
9. Guidelines for the Public Health Management of Pertussis in England (PHE Pertussis Guidelines Group).

2. Mandatory MRSA, MSSA and E. coli bacteraemia and C. difficile infection data (England): up to and including financial year 2015 to 2016

PHE’s latest annual data, and latest Annual Epidemiological Commentary, on trends in reports of Staphylococcus aureus (MRSA and MSSA) and Escherichia coli bacteraemia, and of Clostridium difficile infections, mandatorily reported by NHS acute Trusts in England up to financial year (FY) 2015/16, have been published on the GOV.UK website [1,2].

The data and commentary, including tabular and graphical information, update the previous report published on 9 July 2015. Some key facts are listed below.

2.1 MRSA MSSA and E. coli bacteraemias

A total of 819 cases of MRSA bacteraemia were reported by NHS acute trusts in England between 1 April 2015 and 31 March 2016. This is an increase of 2.4% from 2014/15 (800 cases), and a decrease of 81.6% from 2007/08 (4,451 cases).

Since April 2013, all MRSA cases have been subject to a Post Infection Review (PIR) [3]. The data on the PIR show a consistent decline in the rates of CCG-assigned cases from 0.8 cases per 100,000 population in 2013/14 to 0.5 cases per 100,000 population in 2015/16. Rates of trust-assigned MRSA bacteraemias fell from 1.2 cases per 100,000 bed days in 2013/14 to 0.9 in 2014/15, after which trust-assigned rates remained steady at 0.9 in 2015/16. The rate of third party assigned cases has increased from 0.2 to 0.4 per 100,000 population. Some of the decline seen in the rates of CCG or trust-assigned cases will have been due to the introduction of third party assignment.

A total of 10,586 cases of MSSA bacteraemia were reported by NHS acute trusts in England between 1 April 2015 and 31 March 2016. This is an increase of 7.5% from 2014/15 (9,845 cases), and an increase of 20.7% from 2011/12 (8,767 cases). The rate of all MSSA cases per 100,000 population, per year has risen from 16.4 in 2011/12 to 19.4 in 2015/16. In contrast to the all-MSSA case rate, the incidence rate for trust-apportioned MSSA cases has remained approximately stable (from 8.1 in 2014/15 to 8.4 per 100,000 bed days in 2015/16, a change of 3.6%).

A total of 38,132 cases of E. coli bacteraemia were reported by NHS trusts in England between 1 April 2015 and 31 March 2016. This is an increase of 6.6% from 2014/15 (35,764 cases), and an increase of 18% from 2012/13 (32,309 cases). The rate of E. coli cases per 100,000 population has risen from 60.4 in 2012/13 to 70.1 in 2015/16.

Unlike the interventions for MRSA that were hospital and device related, effective interventions for MSSA and E. coli bacteraemia will need to include the community setting if we are to see the magnitude of reductions seen with MRSA.

2.2 Clostridium difficile infections

A total of 14,139 cases of Clostridium difficile infection were reported by NHS trusts in England between 1 April 2015 and 31 March 2016. This is a decrease of 0.4% from 2014/15 (14,192 cases), and a decrease of 74.5% from 2007/08 (55,498 cases). The rate of all CDI cases per 100,000 population, per year has fallen from 107.6 in 2007/08 to 26.0 in 2015/16.

Of the 14,139 total cases reported in FY 2015/16, 5,164 were trust-apportioned (14.9 per 100,000 bed-days). The trends in incidence rate for trust-apportioned CDI cases has been steeper than that for all cases, with rates declining between 2007/08 and 2013/14 and then remaining stable over more recent FYs (up to and including 2015/16). The rate of trust-apportioned CDI cases decreased from 15.1 in 2014/15 to 14.9 in 2015/16, a change of just 1.5%.The number of trust-apportioned cases fell from 33,434 cases in 2007/08 to 5,164 cases in 2015/16, a decline of 84.5%. The number of non-trust-apportioned cases fell by 59.3% from 22,064 in 2007/08 to 8,975 in 2015/16.

The recently observed increases and subsequent levelling off of CDI numbers and rates are currently under investigation and Public Health England is working closely with the NHS and the wider health service to look for any underlying reasons. In particular, the proportion of infections that detected in the community that maybe associated with recent hospital stays. It is however, important to remember that these recent increases are very minor in magnitude compared to the large and rapid declines observed in earlier years.

2.3 References

1. PHE (July 2016). Quarterly counts by acute Trust and CCG, and financial year counts and rates by acute Trust and CCG, up to financial year 2015 to 2016: * MRSA bacteraemia; * MSSA bacteraemia; * E. coli bacteraemia; * C. difficile infections.

2. PHE (7 July 2016). Annual Epidemiological Commentary: MRSA, MSSA and E. coli bacteraemia, and C. difficile infection data, up to and including financial year 2015/16.

3. NHS England (2014). Zero tolerance – guidance on the post infection review.

3. Infection reports in this issue of HPR

The following reports are published in this issue of HPR. The links below are to the relevant webpage collections:

• Enterococcus spp. bacteraemia: voluntary surveillance reports (EWNI): 2015
• Infections among people who inject drugs (EWNI) annual report.

According to the annual update on voluntarily reported Enterococcus species bacteraemia, the overall rate of infections was 11.2 per 100,000 population in 2015, in EWNI. Reports increased by 19% over the survey period, 2011 to 2015. In 2015, 41 per cent of enterococcal bacteraemia in England were reported as Enterococcus faecalis: slightly higher in both Northern Ireland (42%) and Wales (50%). The rate of enterococcal bacteraemia was highest in those aged 75 years and over (47.7/100,000 population) and those aged less than one year (35.7/100,000). In England, the proportion of isolates showing vancomycin resistance among all Enterococcus spp. from bacteraemia in England increased each year from 10% in 2011 to 17% in 2015.