Thursday 10 January 2008
Epidemiological updates
Scientific advances
Public health developments
Meetings and workshops
Request for Contributions
Seasonal Influenza – European Status
Text updated from: European Influenza Surveillance Scheme (EISS) Weekly Electronic Bulletin
The next EISS update for week 2 will be published on Jan 18th 2008
Increased levels of influenza activity in seven European countries and low levels across the rest of Europe
Summary: There is currently increased influenza activity in England, Ireland, Italy, Luxembourg, Slovenia, Spain and Switzerland. In France and Portugal levels of influenza activity are around the baseline threshold. All other countries reported low levels of influenza activity. Of the total virus detections since week 40/2007 (N=1475), 82% were influenza A of which about 95% were of the H1 subtype.
Epidemiological situation - week 01/2008: For the intensity indicator, the national network levels of influenza-like illness (ILI) and/or acute respiratory infection (ARI) were medium in England, Ireland, Italy, Luxembourg, Slovenia, Spain and Switzerland, whilst they remained low or became low again in 19 other countries that reported this indicator. For the geographical spread indicator, three countries (England, Spain and Switzerland) reported regional influenza activity, five countries local activity, 13 countries sporadic activity and five countries reported no influenza activity. Definitions for the epidemiological indicators can be found here.
Cumulative epidemiological situation - 2007-2008 season (since week 40/2007): So far this season, the consultation rates for ILI and/or ARI have been at levels usually seen outside the seasonal influenza peak period (i.e. below or at the national baseline threshold) in most countries in Europe. A medium intensity of influenza activity (i.e. consultations rates were above the national baseline threshold) was first reported in Bulgaria (in week 48/2007), Austria (50/2007), Northern Ireland (50/2007) and Spain (week 51/2007). In week 01/2008 intensity remained at medium level in Spain and England, Ireland, Italy, Luxembourg, Slovenia and Switzerland started reporting a medium intensity.
Virological situation - week 01/2008: The total number of respiratory specimens collected by sentinel physicians in week 01/2008 was 643, of which 143 (22%) were influenza virus positive; 44 (31%) type A not subtyped, 79 (55%) type A subtype H1 [of which 23 were A(H1N1)], one (1%) type A subtype H3 and 19 (13%) type B. In addition, 187 influenza virus detections were reported from non-sentinel sources (e.g. specimens collected for diagnostic purposes in hospitals), of which 130 (70%) were type A not subtyped, 28 (15%) type A subtype H1 [of which 14 were A(H1N1)] and 29 (15%) type B.
Cumulative virological situation - 2007-2008 season (since week 40/2007): Based on (sub)typing data of all influenza virus detections since week 40/2007 (N=1475; sentinel and non-sentinel data), 599 (41%) were type A not subtyped, 588 (40%) were A(H1), 28 (2%) were A(H3) and 260 (17%) were B.
Based on the antigenic and/or genetic characterisation of 268 influenza viruses, three were A/New Caledonia/20/99 (H1N1)-like, 216 were A/Solomon Island/3/2006 (H1N1)-like, two were A/Wisconsin/67/2005 (H3N2)-like, seven were A/Brisbane/10/2007 (H3N2)-like, 24 were B/Florida/4/2006-like (B/Yamagata/16/88 lineage) and 16 were B/Malaysia/2506/2004-like (B/Victoria/2/87 lineage) (click here).
Comment: Consultation rates for ILI and ARI reported are affected by seasonal holidays. Since this report is based on a week which includes New Year’s Day (1 January), usual patterns of access to primary care and patient swabbing procedures were probably disrupted and the reported consultation rates could be lower than an equivalent non-holiday week. Hence reported rates should be interpreted cautiously.
Despite this, the current data indicate that confirmed influenza activity is increasing in 16 European countries (see intensity map) and a further increase in influenza activity in the coming weeks can be expected. Countries reporting a medium intensity were located in Northern (England and Ireland), Southern (Italy, Slovenia, Spain) and Western (Luxembourg and Switzerland) Europe [according to the UN Geographical Regions]. In the rest of Europe, the ILI and/or ARI consultation rates are currently below the national baseline level but if the pattern of previous seasons is repeated it is likely that some or many of those countries will also see rises.
Overall, for Europe as a whole, 82% of total virus detections since week 40/2007 (N=1475) have been influenza A, of which 95% were of the H1 subtype (calculation excludes the type A not subtyped virus detections). The characterisation data reported to EISS since week 40/2007 indicate that there seems to be a good match between the circulating A(H1) virus and the corresponding vaccine strain A/Solomon Island/3/2006 which is included in the 2007-2008 vaccine (click here).
Background: The Weekly Electronic Bulletin presents and comments influenza activity in the 31 European countries that are members of EISS. In week 01/2008, 26 countries reported epidemiological data and 28 countries reported virological data to EISS. The spread of influenza virus strains and their epidemiological impact in Europe are being monitored by EISS in collaboration with the WHO Collaborating Centre in London (United Kingdom) and the European Centre for Disease Prevention and Control in Stockholm (Sweden).
Full interactive EISS bulletin including maps and graphs by country and informative links in the text
National/regional bulletins in Europe and other bulletins from around the world
Links to general information from EISS:
General information on EISS, including background, membership and information on citing the EISS bulletin
Definitions of epidemiological indicators used by EISS
AVIAN INFLUENZA
There are fluctuating reports in the media of influenza A/H5N1 and other avian influenza infections in birds and humans. ECDC monitors these carefully as part of its epidemic intelligence work. However without laboratory confirmation ECDC only rarely mentions these media reports in this output.
AVIAN INFLUENZA – HUMAN HEALTH – P.R CHINA
10th January 2008
The Chinese Ministry of Health have released a statement (in Mandarin (1)) suggesting that human to human transmission may have occurred in recent cases of H5N1 in a father and son in China, as reported by WHO on 9th December (2). In response to the familial link between the two recent cases in China, ECDC conducted a rapid threat assessment in December on the risks to public health from the event (3), which concluded that at the time it was too early to tell if human to human transmission occurred in this case, but that limited human-to-human transmission is not new, and that such transmission in itself was not a casue for concern. The first such transmission occured in 1997 and have probably been occuring rarely more recently. Hence ECDC would not change its EU risk assessment in the absence of enlarging clusters and chains of transmission of H5N1 which are not being seen at present.
1) Chinese Ministry of Health press release on H5N1 transmission between family members in China in December 2007 (in Mandarin)
2) Avian influenza update from WHO-– situation in China, December 9th 2007
3) ECDC threat assessment: A cluster of 2 cases of avian influenza A/H5N1 in China, December 2007, Stockholm. 11 December 2007
Otherwise, WHO has not reported any cases of H5N1 in humans during the previous seven days. The most recent cases were reported from Egypt on 3rd January 2008.
Cumulative Number of Confirmed Human Cases of Avian Influenza A/(H5N1) Reported to WHO (updated 3rd January2008).
H5N1 avian influenza: timeline of major events (updated 2nd January 2008).
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AVIAN INFLUENZA – ANIMAL HEALTH- UK
10th January 2008
The UK authorities have confirmed H5N1 has been detected in three wild swans at a bird sanctuary in Dorset, in the south of the UK. These are the first positive cases of H5N1 in wild birds in the EU since mid-August 2007.
In response to the outbreak, the UK authorities have established of a control area and larger monitoring area around the positive finding in accordance with EU legislation on highly pathogenic avian influenza in wild birds. In the control area, measures such as enhancing on-farm biosecurity, and banning hunting and the movement of poultry except for slaughter have been adopted with the aim of at preventing the spread of avian influenza from wild birds to poultry or other captive birds, as well as avoiding the contamination of products.
In terms of public health, the risks from infection from wild birds is considered to be very low; it is suggested that only a single outbreak of H5N1 human infection has ever been suspected from wild birds, and that was related to people closely handling and defeathering sick and dead birds in Azerbaijan (1). Hence while it remains important that individuals who are handling dead birds, particularly those that are known to or suspected as being infected with H5N1 take adequate precautions such as wearing gloves and other protective equipment (2), advice to the general public is that they need only follow simple measures already specified by European authorities and WHO such as not handling birds found dead and avoiding unnecessary contact with live birds when A/H5N1 has been shown to be present in a country.(3)
UK Department for Environment, Food and Rural Affairs- press release: Avian Influenza H5N1 confirmed in Dorset (10th January 2008).
European Commission press release: Avian influenza H5N1 confirmed in three wild swans in the United Kingdom: authorities applying precautionary measures (IP/08/29, 10th January 2008).
1) WHO Human avian influenza in Azerbaijan, February–March 2006 Weekly Epidemiological Record 2006 81: 183-188 http://www.who.int/wer/2006/wer8118/en/index.aspx
2) ECDC Technical report: Minimise the Risk of Humans Acquiring Highly Pathogenic Avian Influenza from Exposure to Infected Birds or Animals Version December 21th 2005
3) ECDC Technical report: The Public Health Risk from Highly Pathogenic Avian Influenza Viruses Emerging in Europe with Specific Reference to type A/H5N1 Version June 1st 2006
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AVIAN INFLUENZA – ANIMAL HEALTH- ISRAEL
3rd January 2008
The OIE have reported that Israel has confirmed an outbreak of H5N1 in a small mixed flock of pet birds kept at a kindergarten in the region of Haifa in the west of Israel. The flock of 12 chickens, eight ducks and six pigeons were culled, and restrictions placed around the site of infection.
ECDC comment (9/01/08): The birds were reported to be kept as pets at a kindergarten and hence it is likely they have been handled extensively by children. The potential human health risk from this outbreak may therefore be considered to be higher than cases in an industrial farm (see ECDC Document on groups at high risk). However, there have been no reports of any human infection associated with this case to date.
OIE report of H5N1 outbreak in Israel, including location map (3rd January).
ECDC Guidance on who is at risk of avian influenza May 2006
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AVIAN IAVIAN INFLUENZA – ANIMAL HEALTH- VIET NAM
7th January 2008
The Vietnamese authorities have reported to the OIE a number of outbreaks of H5N1 in four regions in both the north, south and centre of the country over the previous two months (from 10th November 2007). The majority of outbreaks are in duck flocks that have either not been vaccinated as part of the national vaccination campaign, or were infected immediately following vaccination, and hence the vaccine may not have had time to induce sufficient antibody titres to offer protection from infection. The OIE reports that the Vietnamese authorities have carried out culling and other containment measures in response to the outbreaks.
ECDC Comment (9/01/08): These reported outbreaks are part of a wave of H5N1 infection that has been present in Vietnam since May 2007, and affecting poultry flocks across the country. Regular and comprehensive reports from FAO mission in Vietnam (see below) give updates of the animal health situation. The most recent report from 9th January highlights that two provinces (Tra Vinh in the south and Thai Nguyen in the northern Vietnam) have reported HPAI H5N1 in poultry in the last 21 days, and that the ongoing vaccination programme which began in October, is underway in 63 provinces (excluding Ho Chi Minh City). To date, 156.97 million poultry have been vaccinated, of which 90.88 million are chickens and 66.09 million are ducks. Since May, the World Health Organization has reported eight human cases in the country of which 5 were fatal, 3 recovered. The latest human case was reported on 28 December 2007 (4-year-old boy from Son La province).
OIE report of H5N1 outbreaks in Viet Nam, including location map (7th January).
FAO mission report on latest animal health situation in Viet Nam- updated on 9th January.
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Scientific advances
Deaths following influenza vaccination-background mortality or causal connection?
Kokia E. S. et al
Vaccine 2007; 25: 8557-8561.
Background and Description: In the autumn of 2006 there was a high profile incident when four people died in Israel seemingly shortly after they received seasonal influenza vaccination.(1) At the time, the authorities took a very precautionary approach and called a short-lived halt in the vaccination programme in Israel. Following an internal review the authorities felt this was more likely to be a coincidence (the programme was targeting individuals who were at highest risk of sudden death due to underlying cardiac and other conditions) and the programme resumed. However there was a reduction in vaccine uptake as a consequence. There was considerable reporting of the event in the media in some EU countries and ECDC worked with the Israeli and WHO European region authorities and undertook an independent risk assessment which came to the same conclusion. (2) This independent and scientific paper uses population-based estimates of mortality in high risk populations to assess if the deaths that preceded vaccination in Israel were linked to vaccination, or could be attributed to general mortality. The paper supports the conclusion of the Israeli Ministry of Health that the deaths were not related to the vaccine, and more generally, that a mortality rate of between 0.01-0.02% should be expected in such populations over a 7 day period, including in the week following vaccination. This paper also supports the general conclusion that influenza vaccination is not associated with increased risk of death in the short term.
ECDC Comment (9/01/08): The case highlighted in the paper reduced public confidence in vaccination against influenza in Israel, and also evoked commentary further a field (1, 2). More generally, similar ’scares’ may reduce uptake and negatively impact on future vaccination programmes. The cases in Israel demonstrate the importance of critically assessing base-line epidemiological data to determine if mortality following vaccination can be considered to be in access of the norm. In this case, the analysis strongly suggests that the mortality that was observed in Israel was within the confidence levels of that which would be normally expected in the populations groups who received vaccine, irrespective of their vaccination status. For the elderly population in the study, this is between 0.01 and 0.02% in a 7 day period. This gives a useful base-line value which allows genuine adverse events following vaccination to be defined more clearly in such populations if they were to occur in future, and also gives important information that may be used to quickly refute future unsubstantiated ’scares’ associated with mortality in vulnerable populations following immunisation, and thus allow vaccines to continue to be used with confidence. Recent fact sheets prepared by ECDC for citizens (3), and health professionals (4), highlight the value of vaccination against seasonal influenza in high risk groups such as the elderly and those with chronic illness. Although no reliable data exists for vaccine coverage across the EU, an informal study by ECDC last year found national coverage rates varying among older people from as low as 4% to as high as 80%, so it remains important to build and retain public confidence in vaccine efficacy and safety as estimates from ECDC suggest that thousands of lives could be saved if more people in higher risk groups were vaccinated in EU countries. (5) Further scares related to mortality following influenza vaccination are likely to occur because groups who receive the vaccine are commonly the old or those in poor health, and are therefore at higher risk of sudden death. This paper should give those in charge of programmes confidence that though they always must consider the individual facts and the possibility of a causal relationship, the default position should be to carry on vaccinating.
1) Influenza team (ECDC). No link established between deaths in elderly patients in Israel and influenza vaccination. Euro Surveill 2006;11(10):E061026.1. Available from: http://www.eurosurveillance.org/ew/2006/061026.asp#1
2) Sudden deaths and influenza vaccinations in Israel - ECDC Interim Risk Assessment Stockholm, October 2006.
3) ECDC citizen fact sheet: Information on what influenza is and how vaccines can help people in high-risks groups to reduce their chances of becoming seriously ill, Stockholm December 2007.
4) ECDC fact sheet for health professionals: Seasonal Human Influenza and Vaccination – The Facts. Stockholm, December 2007.
5) ECDC press release: Vaccinating “high risk groups” against seasonal flu could save thousands of lives says ECDC, 10th December 2007.
Comment to influenza@ecdc.europa.eu.
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Public health developments
P. H. DEVELOPMENTS- SEASONAL INFLUENZA- TRANSMISSION
Influenza transmission and the role of personal protective equipment: an assessment of evidence – Report from the Council of Canadian Academies’ expert panel on Influenza.
The long awaited report from the Canadian group (1) examines the evidence base for the mechanisms of influenza transmission, and in light of the evidence base, gives an assessment of the effectiveness of wearing masks to reduce transmission of seasonal and pandemic influenza.
The report duplicates previous reports that there remains a surprising lack of evidence on the basic mechanisms of influenza transmission. However the expert panel identified that expulsion of virus particles in the air, such as through sneezing, coughing etc or through aerosol generated medical procedures, and the direct transfer of virus via contact with respiratory secretions on surfaces were the most likely routes the virus is expelled from the respiratory tract. Virus that transmits to a new host either via inhalation of the virus particles from the air ( ’inhalation transmission’), or by self inoculation from a contaminated surface.
In regard to airborne transmission, the expert panel highlighted that the size of the particles expelled has an important impact on dispersal, and hence potential infectivity; they differentiate between ballistic particles- larger particles that are predominately affected by gravity whose infection range lies close to infectious person- probably limited to a metre, and inhalable particles, which are likely to be dispersed further and are may survive in ambient air for many hours. The panel also highlighted that the size of particle also influences where in the respiratory tract of a potential host the virus is inhaled and deposited. The panel noted that the US CDC had recently reconsidered the short-range transmission of influenza, and extended this from 1 metre to 2 metres. While inhalation of particles over a longer range than two metres remains feasible, evidence for such transmission is sparse, and therefore the panel concluded that the current evidence base suggests that influenza is primarily transmitted via inhalation over short distances.
In regard to contract transmission, the panel stressed the lack of evidence for it’s occurrence, but given that influenza viruses have been shown to persist on external surfaces for up to 24 hours, it is reasonable to assume that contract transmission via hands through the mucous membranes of a potential host is likely to occur.
In regard to protective measures against influenza, and particularly respirators and surgical masks, the report again highlights the lack of evidence, but that in regard to ’N95’ respirators, they are designed to capture both ballistic and inhalable particles, and hence are likely to offer protection from inhalation of influenza. Surgical masks are unlikely to capture inhalable particles, but both offer a physical barrier to large ballistic droplets and oral/nasal infection following contact with contaminated surfaces, and masks also prevent infected persons from expelling infected particles into the environment. However the effectiveness depends greatly on the correct fitting of the respirator or mask. The physiological and psychological challenges in wearing such equipment when carrying out normal tasks is also highlighted, and may greatly effect compliance to wearing both surgical masks and respirators.
ECDC comment (9/01/08): The work of the expert panel is another summary of the current status of knowledge on influenza transmission and countermeasures to contain infection, and captures much of the work that has been done on how influenza spreads between people (e.g. 2, 3). However ECDC’s conclusion on this and other reports is simply that not enough is known about some of the basic mechanisms of influenza transmission and especially how it is best interrupted and therefore there is not a lot of point of having further groups of experts reviewing the evidence and data if those data are insufficient to come to any practical conclusion. Without such base line data, gathering evidence for the effectiveness of any intervention is very difficult. There is, therefore, a need for more practical research to address some of the key knowledge gaps in influenza transmission especially on what interventions work and are practical. Such work would provide a meaningful evidence base to help identify the most effective mechanisms by which the spread of both seasonal and pandemic influenza can be reduced. It is therefore somewhat disappointing that the report does not explicitly list areas where further research is needed; ECDC has attempted to identify some key research questions that should be addressed (4), and will continue to advise funding organisations (such as the EU’s DG Research) to highlight where work could usefully be directed.
What the report also does not do is to consider some of the health economic and pragmatic aspects and experiential evidence such as
- whether the deployment of infection control materials in ordinary health care settings (as distinct from settings where transmission is at high risk) represents the best use of monies?
- Whether health care workers in ordinary work can and will use personal protective equipment without major falls in efficiency of working?
Some European work suggests that the current answer to the second question in Europe would be ’no’.(5) Of course that does not apply in the high-risk situations (e.g. doing respiratory aspirations of an influenza infected patient) where PPE is recommended and can be made to work with high staffing levels and scrupulous procedures.
Concerning the one or two metre separation rule. There is no absolute cut-off but ECDC sees not evidence here to shift from the position generally accepted in Europe that most of the risk of droplet transmission of influenza takes place when there is less than one metre separation between individuals.(6) Increasing the distance might be desirable theoretically but there is no evidence of benefit and its scarcely practical.
The report rightly highlights that there is no single countermeasure that will be practical and useful to limit influenza spread. Instead a multi-compenment ’hierarchy of control will be required to present an effective barrier to transmission. This includes the use of personal protective equipment and good hygiene practises, but will also include the use of antivirals and vaccines, and in the event of a pandemic or severe epidemic, possible societal measures to limit contact between people. ECDC has recently produced a ’menu’ of public health measures that may be deployed in the event of an Influenza Pandemic or severe epidemics of seasonal influenza. This highlights the evidence base for each possible measure, and possible effectiveness of each. It also highlights that one measure alone will not be as effective as a Multiple Layered approach. The Menu is currently on the ECDC website in a consultation version, and ECDC would welcome comments on the document. (7) to the usual email address influenza@ecdc.europa.eu
1) Influenza and Personal Protective Respiratory Equipment- an assessment of evidence – Report from the Council of Canadian Academies’ expert panel on Influenza, December 2007.
2) ECDC scientific advice: How seasonal and pandemic influenza transmits between people Modes of Influenza Transmission – Implications for Control.
3) Goldfrank L.R. and Liverman C.T. (2007) ’Preparing for an influneza pandemic: Personal Protective Equipment for Healthcare Workers’. Washingtom: Insitute of Medicine.
4) Influenza team (ECDC). Influenza transmission: research needs for informing infection control policies and practice. Euro Surveill 2007;12(5):E070510.1. Available from: http://www.eurosurveillance.org/ew/2007/070510.asp#1
5) UK Department of Health. Scientific Advisory Group on Pandemic Influenza, Review of the evidence base underpinning clinical countermeasures and risk from H5N1 August 2007
Department of Health UK, http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_077276 (Download document The Use of facemasks during an influenza pandemic)
6) ECDC Personal Measures for Reducing the Risk of Influenza Transmission October 2006 http://ecdc.europa.eu/documents/pdf/PPHM_Recommendations.pdf
7) ECDC Background Advice on Public Health Measures that may be deployed in the event of an Influenza Pandemic or severe epidemics of seasonal influenza- consultation version.(December 2007, Stockholm)
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Comment to influenza@ecdc.europa.eu.
Meetings and workshops
Bangkok International conference on Avian Influenza 2008: Integration from Knowledge to Control
Bangkok, Thailand. January 23-25.
Participants and speakers at the meeting are primarily from the host country and neighbouring countries in south east Asia, the area most affected by avian influenza to date, with some contributions from the international scientific community.
Conference information can be found at: http://www.biotec.or.th/AIconf2008/home/index.asp
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Birdflu 2008: Avian Influenza and Human Health
Oxford, UK. 10-11 September 2008
The first annual Oxford avian influenza conference, BirdFlu2008, will address most aspects of basic and applied research on avian influenza viruses and their potential health and socio-economic impact on humans.
Conference information can be found at: http://www.libpubmedia.co.uk/Conferences/BirdFlu2008/Home.htm
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3rd ESWI European Influenza Conference
Vilamoura, Portugal. 14-17 September 2008.
The European Scientific Working group on Influenza (EWSI) - an independent group of European scientists promoting the study of influenza – will hold its third European Influenza Conference in the autumn of 2008. Deadline for early registration is 31st January.
Conference information can be found at: http://www.eswiconference.org/
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Contributions Requested
The ECDC influenza project team very much welcomes potential contributions to these web updates from EU/EEA member states particularly concerning public health developments and scientific published papers. This includes publications in non-English languages. These should be sent, preferably with a web-link, to Influenza@ecdc.europa.eu. If drawing to our attention a non-English language article for development, a short summary in English is appreciated. However, this is not essential because of its multi-national staff, ECDC can cope with most languages from within the EU.