• Confirmed measles cases in England and Wales: an update to end-December 2008
  
  
• Outbreak of influenza at an acute hospital in north-west England
  
  

 

Confirmed measles cases in England and Wales: an update to end-December 2008

The number of confirmed measles cases with onset in December 2008 was 113 in England and Wales (table), bringing the provisional total for 2008 to 1,348, nearly 40% higher than the 2007 total of 990. As in November, the majority of the laboratory confirmed measles cases in December were outside of London [1]. This is reflected in the proportion of samples tested where measles IgM or RNA was detected, which was higher in the rest of England and Wales (28%) compared to London (14%).

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

Month	Lond-on	East Mids	East of Engl'd	North East	North West	Sth East	Sth West	West Mid's	Wal's	York & Humb	N/k
Jan	60	2	8	1	1	1	-	3	1	11	-
Feb	44	-	4	3	-	7	-	-	-	3	-
Mar	67	1	1	-	-	6	1	1	1	5	-
Apr	94	2	8	3	1	6	15	2	-	15	-
May	103	1	6	-	23	4	7	3	-	4	-
June	100	-	10	1	22	7	3	5	-	3	-
July	68	1	10	-	22	17	3	8	-	2	-
Aug	31	6	8	-	14	17	-	6	-	2	-
Sep	30	5	3	-	7	2	-	9	21	-	-
Oct	42	11	5	2	37	11	1	9	14	1	1
Nov	14	8	10	2	32	26	2	33	1	1	-
Dec	9	8	11	3	21	23	6	30	1	-	1
Total	662	45	84	15	180	127	38	109	39	47	2

Cases during December were confirmed from all regions except Yorkshire and Humber. The majority of the disease burden was concentrated in the North West, South East and the West Midlands. These regions have continued to see cases associated with outbreaks reported previously from nurseries, primary and secondary schools (see table). In addition, the East of England had an outbreak involving 25 cases in a private boarding school. Most of the affected students, including some foreign citizens, were boarders at the school.

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

Cases are still being identified in the age groups targeted by the MMR catch-up campaign announced in August 2008 (figure 2) [2]. Overall in 2008 73% of all laboratory confirmed cases were between 1 and 18 years: 1 to 4 years (341 cases), 5 to 9 (299 cases), 10 to 14 (236 cases) and 15-18 (107 cases).

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

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

* One case with unknown age not included.

References

1. HPA. Confirmed measles cases in England and Wales - an update to the end of November 2008. Health Protection Report [serial online] 2009, 3(1); news. Available at: http://www.hpa.org.uk/hpr/archives/2009/news0109.htm#msles.

2. HPA. MMR catch-up programme announced. Health Protection Report [serial online] 2008, 2(32); news. Available at: http://www.hpa.org.uk/hpr/archives/2008/news3208.htm#mmr.

Outbreak of influenza at an acute hospital in north-west England

An outbreak of influenza occurred amongst patients and staff at an acute hospital in the North West of England in early December 2008. The response to the outbreak, recorded here, illustrates the value of prevention and control measures, including vaccination of health care workers, in containing such outbreaks.

Over a three-week period in November/December 2008, rates of influenza-like illness in Liverpool increased from 26.7 per 100,000 population (in week 47) to 102.7 per 100,000 (in week 50) [1,2]. At the same time cases of influenza started presenting at the Royal Liverpool University Hospital. On 25 November a confirmed case of influenza, acquired in the hospital, was diagnosed on the haematology ward.

By 5 December, the total number of confirmed influenza A cases had increased to 11 patients and five members of staff. Four of the cases were on the haematology ward and three on the renal ward, the others were seen in either A&E or at outpatient clinics. An outbreak was then declared and an outbreak control group convened. Active case searching was undertaken amongst patients and staff.

In total there were 115 confirmed cases of influenza A: 95 in patients, 22 in healthcare workers who were symptomatic while at work and two in visitors to some of the affected areas (see figure). There was a mixture of community and hospital acquired infections. The majority of the confirmed influenza A cases (85) were of subtype H3 and seven were H1. All the H1 subtypes were isolated from haematology patients, this being a distinct cluster within the outbreak.

The outbreak lasted six weeks. The epidemic curve (figure) shows a rapid increase in cases over the first two weeks, reaching a plateau in the third week and a subsequent decline over a three week period. Control measures were put in place towards the end of week 49.

Epidemic curve of confirmed influenza cases, Royal Liverpool University Hospital, and influenza-like illness rates in Liverpool between week 47/2008 and week 2/2009

The following control measures were implemented: high risk (eg immunosuppressed) cases were treated with antiviral drugs; high risk contacts in the affected wards were given antivirals as prophylaxis; relatives and visitors eligible for seasonal influenza vaccine were advised to get immunised by their GP; and symptomatic staff were excluded from duties and tested if they had symptoms while at work. Confirmed cases were isolated. Suspected cases were also isolated until laboratory confirmation was available. Cohorting of cases was avoided to avoid cross infection with different influenza virus strains.

The first laboratory-confirmed case was screened for oseltamivir resistance and an H1 virus strain, resistant to oseltamivir, was identified. As a high proportion of the viruses from confirmed influenza cases were initially infected with H1 virus, and were therefore likely to be oseltamivir-resistant, zanamivir was used for treatment and prophylaxis for hospital-acquired cases in the affected areas.

In addition, all staff who had not previously taken up the offer of vaccination against seasonal influenza were offered it again. Staff in affected wards were targeted in the first instance. When these areas where covered, vaccination was offered in other high risk areas within the hospital and subsequently to all staff. Vaccination sessions were organised out of normal working hours to capture those working at night or at weekends, thus helping to maximise take up at ward level. In total over 1,299 staff were vaccinated in the first two weeks of the outbreak.

At the same time, a letter was send to all GPs in Liverpool highlighting the high levels of influenza in the community and urging them to immunise those in the at-risk groups who had not already been vaccinated during the 2008/09 season.

Over the Christmas period the number of cases acquired in hospital reduced, despite influenza-like illness rates in the community remaining above the baseline threshold (30 per 100,000) [3]. The last confirmed case in hospital was on 2 January 2009. The outbreak was closed on 6 January.

The outbreak illustrated how easily influenza can spread in a health care setting when virus is circulating in the community and staff vaccination levels are low. It was a notable success in the management of the outbreak that high levels of vaccination were achieved in a short period of time, helping to reduce the exposure of vulnerable patients in hospital despite the ongoing seasonal influenza activity in the community.

References

1. North West Influenza Bulletin. HPA NW Surveillance of Influenza Activity 2008/2009. Bulletin 8, 28 November 2008. Available at: http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1227774033326.

2. North West Influenza Bulletin. HPA NW Surveillance of Influenza Activity 2008/2009. Bulletin 11, 19 December 2008. Available at: http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1229673219383.

3. North West Influenza Bulletin. HPA NW Surveillance of Influenza Activity 2008/2009. Bulletin 15, 16 January 2008. Available at: http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1232094411785.