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Volume 4 No 3; 22 January 2010

New pneumococcal vaccine for children


The Health Protection Agency (HPA) has welcomed the Department of Health's replacement of the current pneumococcal vaccine (PCV) with a vaccine that protects against further strains of the disease [1]. The new vaccine will protect against the seven strains already contained in the current vaccine as well as six further common strains of the infection.

The new vaccine will be given to children according to the same three-dose schedule that is currently followed, children being immunised at two, four and thirteen months of age.

Approximately 5,000-6,000 cases of invasive pneumococcal disease (IPD) are reported annually. According to the latest uptake figures, the percentage of children who have received two doses of the PCV vaccine in the UK by 12 months of age is 92.4% and the number receiving a booster dose of PCV by 24 months is 86.6%.

References
"Health Protection Agency welcomes addition of new pneumococcal vaccine to childhood immunisation programme", HPA press release, 19 January 2010.

Pandemic H1N1 transmission continuing in some countries but declining globally



Global situation

Overall pandemic (H1N1) 2009 influenza activity in the temperate northern hemisphere peaked between late October and late November 2009 and has continued to decline since, according to the WHO's latest updates of the global situation [1].

Nevertheless, in the northern hemisphere the virus could still be causing infections until winter ends in April while it is too soon to say what will happen once the southern hemisphere enters winter. WHO said the most intense areas of pandemic influenza virus transmission currently were in parts of North Africa, South Asia and in limited areas of eastern Europe [1].

The WHO noted that:
  • In North Africa limited data suggest that transmission of pandemic influenza virus remains geographically widespread and active throughout the region but has likely recently peaked in most places;
  • In South Asia active transmission of pandemic influenza virus persists in the northern and western parts of the subcontinent, however overall activity has recently peaked;
  • In Europe pandemic influenza transmission remains geographically widespread across parts of western, central, and south-eastern Europe, however overall influenza activity continued to decline or remain low in most countries. The areas of most intense transmission currently include Poland, Austria, Estonia, Romania, Hungary, and Moldova;
  • In East Asia influenza activity remains widespread but continues to decline overall in most places;
  • In the Americas, both in the tropical and northern temperate zones, overall pandemic influenza activity continued to decline or remain low in most places;
  • In temperate regions of the southern hemisphere sporadic cases of pandemic influenza continued to be reported without evidence of sustained community transmission.

First national health impact assessment

The US Centers for Disease Control and Prevention (CDC) has published an estimate of the overall health impact of the pandemic (H1N1) 2009 in the USA, taking account of data available up until 12 December 2009 [2]. The estimate was carried out after a four-week period (ending 12 December 2009) during which there was only a "modest increase" in the total numbers of cases, hospitalisations and deaths reported in the USA compared with the levels during the peak months.

The CDC stressed that it may never be possible to validate the accuracy of the estimates and that they are intended only to "provide a sense of scale" of the burden of pandemic-related disease and mortality. The true number of cases, hospitalisations and deaths may, indeed, be outside the range of estimates it has arrived at (see table), the report notes.

CDC estimates of pandemic (H1N1) 2009 cases and related hospitalisations and deaths from April to December 12, 2009, by age group*

 

Mid-level range*

Estimated range*

Cases

 

 

0-17 years

~18 million

~12 million to ~26 million

18-64 years

~32 million

~23 million to ~47 million

65 years and older

~5 million

~4 million to ~7 million

Total cases

~55 million

~39 million to ~80 million

Hospitalisations

 

 

0-17 years

~78,000

~55,000 to ~115,000

18-64 years

~145,000

~102,000 to ~213,000

65 years and older

~23,000

~16,000 to ~34,000

Total hospitalisations

~246,000

~173,000 to ~362,000

Deaths

 

 

0-17 years

~1,180

~830 to ~1,730

18-64 years

~8,620

~6,090 to ~12, 720

65 years and older

~1,360

~960 to ~2,010

Total deaths

~11,160

~7,880 to ~16,460

* Deaths have been rounded to the nearest 10. Hospitalisations have been rounded to the nearest thousand and cases have been rounded to the nearest million.


UK situation at 21 January 2010

Key points of the Health Protection Agency's Weekly National Influenza Report of 21 January (week 3) [3] covering the UK situation were as follows:
  • Pandemic (H1N1) 2009 influenza activity was decreasing across the UK;
  • In week 2 (ending 17 January), the weekly influenza-like illness (ILI) consultation rate decreased in all schemes across the UK;
  • The National Pandemic Flu Service continued to issue antiviral drugs to people in England. The number of assessments and antiviral collections decreased over the past week;
  • A decrease in respiratory syncytial virus detections has been observed recently;
  • The main influenza virus circulating in the UK continued to be the pandemic (H1N1) 2009 strain, with few influenza H1 (non-pandemic), H3 and B viruses detected. Thirty-six of 4,949 pandemic viruses tested have been confirmed to carry a mutation which confers resistance to the antiviral drug oseltamivir; three are phenotypically resistant to the drug but retain sensitivity to zanamivir;
  • The majority of pandemic influenza cases continued to be mild. The cumulative number of deaths reported due to pandemic (H1N1) 2009 in the UK was 388;
  • The UK pandemic influenza vaccination programme continues for people at high risk of severe disease, health-care workers and healthy children aged between six months and five years. For further information see the Department of Health website;
  • An outbreak of pandemic (H1N1) 2009 influenza occurred in pigs in Suffolk.  As this virus has been circulating widely in the human population, no public health impacts are expected.

Under-ascertainment of the health impact of the pandemic

Besides its assessment of the overall health impact of the pandemic in the USA, the CDC also noted a number of features that have also been referred in other preliminary reports and assessments in other parts of the world, such as the age-groups disproportionately affected and the vulnerable groups seen to have been most likely to be hospitalised.

The legacy of immunity among those old enough to have been exposed to the 1968 pandemic, for example, is demonstrated in the CDC assessment and in studies of hospitalisations in the Netherlands and France [4,5] while the vulnerability of pregnant women, infants and the obese to complications following infection has also been confirmed [4,5].

The extent of under-ascertainment of levels of infection in the national population is also a theme in a UK paper analyzing data generated by an ongoing Health Protection Agency programme of seroepidemiological research in 2008 and 2009. Analysis of representative blood samples received from across England indicated that in high-incidence areas, such as London and the West Midlands, health impact assessment of the pandemic based on numbers of patients presenting at GP surgeries may have underestimated the true level by ten-fold [6].

Since different methodologies having been used to make national estimates of health impact and mortality, such assessments are not directly inter-comparable. For example, the methodology underpinning CDC's estimates is based primarily on hospitalisation data (generated by the CDC's Emerging Infections Program) which are then extrapolated to derive figures for all cases and associated deaths. In the UK, in contrast, assessment of the total health impact of the pandemic has been based primarily on syndromic surveillance data consisting of GP consultation rates for ILI.

Nevertheless, a common conclusion of preliminary reports is that official surveillance data are likely to have under-estimated the true health impact and mortality levels of the pandemic significantly. Regarding the global extent of under-ascertainment, while the WHO's director general said in January that 13,000-14,000 was a conservative estimate of the number killed directly by the virus (14,000 deaths have been officially reported to the WHO), she noted that WHO experts have said it will take at least 1-2 years after the pandemic ends to establish the true total and that this might exceed the number of laboratory confirmed cases recorded to date [1].

References

1. WHO. Update no. 84 of 22 January 2010 (http://www.who.int/csr/don/en/) and speech by WHO director-general, 17 January 2010 (http://www.who.int/mediacentre/vpc_transcript_14_january_10_fukuda.pdf).

2. CDC. Estimates of 2009 H1N1 influenza cases, hospitalizations and deaths in the United States, April - December 12, 2009, http://www.cdc.gov/h1n1flu/estimates_2009_h1n1.htm.

3. HPA. Weekly National Influenza Report: week 3 (21 January 2010, PDF 440 KB ) , HPA website: www.hpa.org.uk/swineflu/surveillance&epidemiology.

4. Fuhrman C, Bonmarin I, Paty AC, Duport N, Chiron E, Lucas E, et al. Surveillance of hospitalisations for 2009 pandemic influenza A(H1N1) in the Netherlands, 5 June - 31 December 2009. Euro Surveill. 15(2), 14 January 2010. Available at: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19461.

5. Klooster TM VanT, Wielders CC, Donker T, Isken L, Meijer A, et al. Severe hospitalised 2009 pandemic influenza A(H1N1) cases in France, 1 July - 15 November 2009. Euro Surveill. 15(2), 14 January 2010. Available at: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=19463.

6. Miller E, Hoschler K, Hardelid P, Stanford E, Andrews N, Zambon M. Incidence of 2009 pandemic influenza A H1N1 infection in England: a cross-sectional serological study, Lancet (online), 21 January 2010. Available at: http://press.thelancet.com/h1n1inengland.pdf.

Earthquake in Haiti – advice and information for relief workers



A 7.0 magnitude earthquake struck the island of Haiti on 12 January 2010, close to the nation's capital of Port-au-Prince. The quake was felt in the Dominican Republic and as far away as Jamaica. Preliminary reports indicate a significant loss of life; there are no official numbers at this time but thousands of people are dead or missing and there is extensive damage to infrastructure. An international relief effort is now underway. A full summary and regular updates on the situation are available from the World Health Organization.

The Foreign and Commonwealth Office advisesagainst non-essential travel to Haiti at this time. Only those who are part of official relief organisations should travel.

Health professionals can contact the National Travel Health Network and Centre (NaTHNaC) for travel health advice or consult the NaTHNaC Country Information Page for Haiti.

The risk of infectious disease in returning travellers is believed to be low. However, individuals returning from earthquake-affected areas in the coming weeks may have been exposed to environmental conditions that were worse than they had prepared for. Dust inhalation and exposure to the environment (e.g. heat and humidity) are all potential hazards. The immediate health needs among people returning to the UK from Haiti are likely to be psychological, resulting from the trauma, shock and loss that individuals may have experienced. All travellers returning from Haiti are advised to seek advice from their GP if they have health concerns, and should certainly do so if they experience any symptoms.

A dedicated page on the Haiti earthquake has been set up on the HPA website, which contains a risk assessment and advice for those travelling to assist with the relief effort; this will be updated as the situation evolves.

Cessation of enhanced data collection for invasive group A streptococcal disease



The invasive group A streptococcal (iGAS) Incident Management Team decided on 11 January 2010 to discontinue enhanced data collection via local Health Protection Units (HPUs) for cases diagnosed in 2010. Enhanced data collection on iGAS cases was launched by the Incident Management Team in February 2009 following the identification of a rise in incidence of cases and concern over possible increases in case fatality rates [1,2]. Further increases during the Spring resulted in the Inspector of Microbiology issuing an alert to frontline medical staff in April 2009 [3].

Enhanced surveillance captured all cases of severe group A streptococcal infection (cases with sterile site isolates or non-sterile site isolates accompanied by severe clinical manifestations) diagnosed from 1 January 2009. Once informed of cases by local microbiology laboratories, in accordance with pre-existing national guidelines, local HPUs were asked to co-ordinate collection of additional clinical, risk factor and clustering information in liaison with the microbiology department and submit data through a custom-made web-based data capture system. The original objectives set were to: identify any increases in risk of severe GAS infection amongst established or novel risk groups who might benefit from further advice, prophylaxis or other intervention; identify potential improvements in the public health management of both individual cases and clusters and contact follow up; evaluate the epidemiology of severe GAS infection in relation to clinical, risk factor, outcome of cases and possible associations with microbiological characteristics; and use the opportunity of enhanced surveillance to raise general clinical and public health awareness of this condition and recommended public health actions around individual cases. With the subsequent emergence of pandemic (H1N1) influenza, monitoring the impact of pandemic influenza on incidence of severe GAS infection was added to the list of objectives.

Results from the surveillance activities confirmed the increased incidence of iGAS disease during 2008/09, with 1444 isolate referrals made to the CfI’s Respiratory and Systemic Infection Laboratory (RSIL) during that period (September (week 37) 2008 to September (week 36) 2009; figure 1). This was mirrored by increases in scarlet fever notifications, with 4147 notifications made during this period, the highest since 1995/6.


Weekly count of sterile site GAS isolates referred to the CfI Streptococcus and Diphtheria Reference Unit, by specimen date (up to end of week 53/2009, 31 December 2009)

A total of 1440 enhanced surveillance records were entered for cases diagnosed in 2009. Of 1253 questionnaires providing risk factor information, 37% had no underlying illness or co-morbidity, increasing to 67% in children (less than 15 years), with no new risk groups identified to date. Clinical information has been reported in 1380 questionnaires so far, with 19% of patients recorded as having been admitted to intensive care/high-dependency units, rising to 26% among 15-64 year-old adults. Two hundred and thirty three (24%) of 978 records stating outcome were recorded as having died within seven days of diagnosis. Further detailed epidemiological analyses are being undertaken on enhanced surveillance data.

Microbiological characterisation of isolates identified an excess of type emm/M3, with further work being undertaken to examine the molecular characteristics of these emm/M3 strains compared to ones identified in previous years.

With the new season upsurge just beginning, we remind clinicians to remain vigilant and for microbiologists to continue to notify HPUs promptly of incident cases for follow up of community contacts as per current guidelines [4], and to refer all sterile site isolates to the reference laboratory. We further ask HPUs to complete data collection on all cases diagnosed in 2009.

References

1. Lamagni TL, Efstratiou A, Dennis J, Nair P, Kearney J, George R. Increase in invasive group A streptococcal infections in England, Wales and Northern Ireland, 2008-9. Euro Surveill. 2009; 14(5).

2. HPA. Enhanced surveillance initiated for group A streptococcal infections. Health Protection Report [serial online] 2009; 3(8): news. Available at: http://www.hpa.org.uk/hpr/archives/2009/hpr0809.pdf.

3. Increase in invasive group A streptococcal infections in England. Department of Health 2009; CEM/CMO/2009/05. Available at: https://www.cas.dh.gov.uk/ViewandAcknowledgment/ViewAlert.aspx?AlertID=101179.

4. Health Protection Agency Group A Streptococcus Working Group. Interim UK guidelines for management of close community contacts of invasive group A streptococcal disease. Commun Dis Public Health 2004; 7(4): 354-361.