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Volume 4 No 32; 13 August 2010

Diagnosed HIV infection in the UK: 2009 update

An estimated 6,630 individuals were newly diagnosed with HIV in the United Kingdom (UK) in 2009, according to the latest national HIV data published by the HPA. The new data illustrate the changing characteristics of those newly diagnosed with the virus and those seen for HIV care during the reporting period.

Having adjusted for undetermined risk, over half of people newly diagnosed in 2009 (54%; 3,560) probably acquired their infection through heterosexual contact and 42% (2,760) through sex between men (figure 1).

The number of new HIV diagnoses in 2009 is lower than the figure for 2008 (7,388), and represents the fourth year-on-year decline from a peak of 7,982 diagnoses in 2005. The decline is mainly due to lower numbers of new diagnoses among those infected heterosexually abroad, mostly in sub-Saharan Africa; diagnoses among this group have fallen from a peak of 4,230 in 2004 to an estimated 2,430 in 2009.

As a result of this decline, and despite numbers remaining relatively stable over the past three years (1,030 in 2007; 1,150 in 2008; 1,130 in 2009), UK-acquired infections as a proportion of all new diagnoses among those infected heterosexually have increased from 24% in 2007 to 32% in 2009. Of the 1,130 persons infected heterosexually in the UK and newly diagnosed in 2009, an estimated 43% were white and 38% were black-African. The number of new HIV diagnoses among men who have sex with men (MSM), the majority of whom acquired their infection within the UK, remains relatively high. In 2009 there were an estimated 2,760 new diagnoses among MSM compared to 2,780 in 2008 and 2,950 in 2007.

The 6,630 new HIV diagnoses in 2009 contributed to a total of 65,319 people living with diagnosed HIV infection in the UK in the same year. The 2009 figure represents an increase of 7% from 2008 (61,110), and almost a three-fold increase on the number seen in 2000 (22,575). In 2009, almost half (49%, 32,214) of diagnosed HIV-infected individuals were men and women infected via heterosexual contact and 42% (27,427) were men infected through sex between men.

The age distribution of people living with diagnosed HIV infection is changing, with older age-groups increasing both in number and proportion (figure 2). In 2009, almost one in five adults (aged 15 year or older) were aged 50 years or older, compared to one in seven adults in 2005 and one in ten in 2000. This increase is due to effective antiretroviral therapy (ART) improving survival among the diagnosed HIV-infected population, and continued transmission at older ages [1].

The number and proportion of patients prescribed antiretroviral therapy (ART) has increased over the past decade. In 2009, 78% (50,292/64,595) of individuals seen for HIV care were prescribed ART; this compares to 69% (14,051/20,373) in 2000. The 2008 British HIV Association (BHIVA) guidelines recommend that treatment discussions commence when a patient’s CD4 cell count falls to ≤350 cells per cubic millimetre (ccm) [2], (previous guidelines recommended treatment should start when CD4 cells reached below 200 ccm). The proportion of patients with a CD4 count of 201-350 ccm who were not prescribed ART, which fell from 28% (3,236/11,756) in 2007 to 21% in 2008 (2,427/11,758) and 18% (1926/10719) in 2009. The proportion of patients whose CD4 was ≤200 ccm and who were not prescribed ART has remained stable at 15%; the majority of these patients will have been diagnosed recently.

Detailed tables on the UK HIV data for 2009, by geographic region and prevention groups, can be accessed on the HIV section of the HPA website at: http://www.hpa.org.uk/Topics/InfectiousDiseases/InfectionsAZ/HIV/NewHIVDiagnoses/.

Figure 1. New HIV diagnoses in the UK by exposure category, UK: 2000-2009

Figure 2. Diagnosed HIV-infected individuals seen for care by age group, UK: 2000-2009

 

References

1. Smith R, Delpech VC, Brown AE et al. HIV transmission and high rates of late diagnoses among adults aged 50 years and over. AIDS 2010 24:2109-15.

2. Gazzard BG and BHIVA Treatment Guidelines Writing Group. British HIV Association Guidelines for the treatment of HIV-1-infected adults with antiretroviral therapy 2008. HIV Medicine 2008; 9(8): 563-608.

Recent outbreaks and incidents of scombrotoxic fish poisoning in England

Two outbreaks and two incidents of scombrotoxic fish poisoning (SFP) have been reported in England and Wales between the end of June and the end of July. Prior to the end of June, four other incidents of SFP occurred in England during 2010, one in April, two in May and one in early June, affecting six people. SFP outbreaks and incidents are more likely to occur during warmer weather after consumption of fish that has been improperly stored, handled, and prepared [1,2].

The four recent outbreaks/incidents occurred in three regions of southern England (South East, London and East of England). All four were associated with food service premises (restaurants) and three were linked to consumption of tuna and the other to mackerel. Ten people were affected. Remaining product was analysed for histamine from two of the restaurants. Remnants of tuna from one of the restaurants contained highly toxic levels of histamine (>4500 ppm). This suggests poor food handling and inadequate refrigeration during storage at the premises after the tuna packs were opened. In the other, elevated histamine levels (185 ppm) were present in a sealed pack of raw tuna indicative of poor temperature control at some stage post-harvest, storage, transportation, or at the premises.

Surveillance of SFP is based on information submitted to the HPA Foodborne and non-Foodborne Gastrointestinal Outbreak Surveillance System (eFOSS) and on results from samples submitted to the HPA Centre for Infections, Laboratory of Gastrointestinal Pathogens [3]. Between 1992 and 2009, 71 general outbreaks of scombrotoxic fish poisoning (SFP) were reported in England and Wales (between 0 and 10 incidents per year) affecting 336 people. Analysis of outbreaks of foodborne illness associated with fish or fish products over this 18 year period showed that SFP accounted for 56% of these and that SFP outbreaks occurred more frequently in food service settings (75%) and during the summer months.

SFP is associated with the consumption of contaminated fish of the family Scombridae (including tuna, mackerel, herring, marlin, bonito, and jacks). SFP is a chemical intoxication and symptoms occur within ten minutes to two hours after consumption of preformed histamine in scombroid fish and include rash on the face, neck and upper chest, flushing, sweating, nausea, vomiting, diarrhoea, abdominal cramps, headache, dizziness, palpitations, oral burning sensation, metallic taste in mouth, and hypotension. Symptoms may be of sufficient severity to prompt cases to seek urgent medical attention and treatment with antihistamines, but they usually resolve within 24 hours.

Scombroid fish naturally contain high levels of the amino acid histidine, which is converted to histamine as a result of the naturally occurring enzyme histidine decarboxylase producing bacteria if storage conditions are inadequate to control bacterial growth. Histamine is heat stable and survives subsequent processing, including canning, and consumption of fish with elevated levels of histamine can result in illness. Bacterial spoilage and production of histamine may occur at any stage in the food chain (ie from landing the fish, at the processing plant or in the distribution system, or in catering premises or homes) and adequate temperature control is key in preventing bacterial growth and histamine formation. For control of scomboid fish and their products, there are permissible levels set by European Union legislation to protect public health [4]. Accredited chemical tests for histamine are available at the Laboratory of Gastrointestinal Pathogens, and a minimum sample of 10g fish, or fish products, is required for the test. Samples should be frozen to arrive in a frozen state.

Maintenance of microbiological quality from post harvest until the point of consumption is essential if SFP associated with fish is to be avoided. Caterers and consumers need to be aware of these hazards, adopt appropriate control measures, and follow advice provided by the Food Standards Agency [5,6,7] in order to reduce the risk of SFP, ie keeping fish and fish products properly refrigerated to prevent bacterial spoilage and the production of histamine.

References

1. McLauchlin J, Little CL, Grant KA, Mithani V (2006). Scombrotoxin fish poisoning.
J Public Health 28:61-62.

2. Gillespie IA, Adak GK, O'Brien SJ, Brett MM, Bolton FJ (2001). General outbreaks of infectious intestinal disease associated with fish and shellfish, England and Wales, 1992-1999. Comm Dis Public Health 4:117-23.

3. HPA. Electronic Foodborne and non-Foodborne Gastrointestinal Outbreak Surveillance System, England and Wales.

4. European Commission. Commission Regulation (EC) 2073/2005 of 15 November on microbiological criteria for foodstuffs (as amended by Regulation (EC) 1441/2007).

5. Food Standards Agency. Safer food, better business for caterers, http://www.food.gov.uk/foodindustry/regulation/hygleg/hyglegresources/sfbb/sfbbcaterers/

6. Food Standards Agency. Eatwell advice for consumers, http://www.eatwell.gov.uk/healthydiet/nutritionessentials/fishandshellfish/

7. Food Standards Agency. Advice on scombrotoxin in fish, http://www.food.gov.uk/news/newsarchive/2010/aug/sfp.

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DH seasonal influenza vaccine programme report for 2009/10

Uptake of seasonal influenza vaccine during the 2009/10 season fell slightly in England compared with 2008/09, but uptake among clinical risk groups, which has been increasing steadily in recent years, was improved, according to a summary report published by the Department of Health [1].

Population groups eligible to receive the trivalent seasonal vaccine include all individuals aged 65 years or more; and those in a clinical risk group between six months and 65 years.
Compared with the previous season, the national mean uptake level achieved among the over-65’s was 72.4% (slightly lower than the 74.1% achieved in 2008/09). Overall coverage among at-risk groups was 51.6% (compared with 47.1% in 2008/09).

Coverage among over-65’s has remained steady in England in recent years but the 75% population coverage recommended by the WHO has not been achieved since 2005/06. The report suggests that the slight fall in uptake in individuals aged 65 years in 2009/10 may have been due in part to the introduction of the H1N1 influenza pandemic vaccination programme in October 2009. (The effectiveness of the pandemic vaccination campaign is to be the subject of a separate report.)

At-risk groups

Coverage among clinical risk groups has seen a steady rise in England since they were made eligible for the seasonal vaccine in 2004/05, with 2009/10 being the first year that of 50% or more coverage was achieved. Nevertheless, the report notes that a large proportion of the at-risk group population eligible to receive the vaccine remained unvaccinated (approx 2.2 million, 48.4% of the eligible population in 2009/10). Also coverage varies widely between disease groups and by age groups. The diabetes disease group showed the highest uptake while coverage among others, such as those with chronic degenerative neurological disease and chronic liver disease, is lower.

Reference

1. Seasonal influenza vaccine uptake among the 65 years and over and under 65 years at risk in England – winter season 2009-10 (1200 KB PDF), Department of Health, 11 August 2010.

WHO announces official end of the 2009 (H1N1) pandemic

On 10 August, the director-general of the World Health Organization announced that the H1N1 (2009) flu pandemic was over. The announcement was made following a meeting of the WHO Emergency Committee, which reviewed global epidemiological data indicating that the flu virus, worldwide, is transitioning towards seasonal flu characteristics and patterns of transmission.

The decision was prompted by the following observations:
  • H1N1 (2009) Influenza activity is consistent with that seen for circulating seasonal influenza viruses. There are no longer out of season outbreaks being reported in either the northern or southern hemisphere;
  • many countries are reporting a mix of influenza viruses, as is typical for seasonal flu activity;
  • published studies indicate that 20-40% of populations in some areas have been infected and this together with good vaccination coverage in many countries, especially in high-risk groups, has increased community wide immunity.

The H1N1 (2009) virus is still in circulation and it is expected that it will continue to circulate for some years to come. Continued vigilance is extremely important and, like the pandemic, the immediate post-pandemic period is also unpredictable. It is likely that there will be sporadic cases and localised outbreaks of different magnitude and that the virus will continue to cause serious disease in younger age groups at least in the immediate post-pandemic period. Groups identified during the pandemic as at higher risk of more severe disease and fatal illness are likely to remain vulnerable, highlighting the importance of the influenza vaccination programme, though hopefully the number of cases will diminish.

Current H1N1 (2009) global activity

In the northern hemisphere during the past month, pandemic and seasonal influenza viruses activity has been sporadic or at very low levels. In the southern hemisphere, Chile, Australia and New Zealand have all recently detected low levels of predominantly pandemic influenza virus, with clusters of cases reported in the Australian northern territories. In Australia and New Zealand, although there has been a sustained upward trend in the rates of influenza-like illness (ILI) in recent weeks, overall rates remain well below those observed during the same period in 2009 during the first pandemic wave in the southern hemisphere. In Asia, the most active areas of pandemic influenza virus transmission currently are in parts of India, and to a much lesser extent, in parts of Nepal and Bhutan.

The WHO statement on the end of the 2009 (H1N1) pandemic can be accessed at: http://www.who.int/mediacentre/news/statements/2010/h1n1_vpc_20100810/en/index.html.

The latest HPA Influenza Pandemic update (August 2010) has been published and can be accessed at:
http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1281952493270.

The latest HPA weekly national influenza report (12 August 2010) has just been published and can be assessed at: http://www.hpa.org.uk/web/HPAweb&HPAwebStandard/HPAweb_C/1243928258754.

Influenza activity remains very low across the UK - with occasional reports of hospitalised pandemic H1N1 cases, often with links to affected areas. These cases have usually had risk factors for more severe disease.