INFLUENZA
There has been considerable concern of an impending influenza pandemic. I have reproduced below some reports from CDC and WHO of the current influenza status in USA and worldwide. For more information on Influenza please go to http://www.vadscorner.com/influenza.html .
From CDC :
Synopsis: During week 2 (January 9 through January 15), 21% of specimens tested by WHO and NREVSS laboratories for influenza were positive. State and territorial epidemiologists from 30 states reported widespread influenza activity, and 12 from other states reported regional influenza activity. The proportion of patient visits to sentinel physicians for influenza-like illness was 4% overall in the United States, exceeding baseline levels of 0% to 3%, and were above the baseline in 6 of 9 surveillance regions. The proportion of deaths attributed to pneumonia and influenza was 10.5%. This percentage is above the epidemic threshold for week 2 and is unusually high.
During the current season, the overall national percentage of respiratory specimens positive for influenza appears to have peaked at 33% during week 51. During the past 3 years, the peak percentages of respiratory specimens testing positive for influenza viruses have ranged from 28% to 34%. For this season, the percentage of patient visits for influenza-like illness appears to have peaked at 6% during week 52. During the past 3 years, the peak percentages for such visits have ranged between 5% and 7%. So far, the proportion of deaths attributed to pneumonia and influenza (P&I) has not clearly peaked. During the previous 3 years, P&I mortality levels have peaked between 8.8% and 9.1%. The current season's P&I figures must be interpreted with caution because important changes have taken place in this year's case definition that may be contributing to higher estimates of P&I mortality than in previous years.
U.S. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) Collaborating Laboratory Reports*: During week 2, WHO and NREVSS laboratories tested 2,089 specimens for influenza viruses and 449 (21%) were positive. One hundred twenty-two were influenza A(H3N2) viruses, 318 were unsubtyped influenza A viruses and 9 were influenza type B. In 3 regions (New England, West North Central, and West South Central), more than 30% of specimens tested over the past 3 weeks (weeks 52 through 2) were positive for influenza (range 31% to 37%). In the remaining 5 regions, the percentage of specimens testing positive for influenza ranged from 15% to 29% during the past 3 weeks.
Since October 3, WHO and NREVSS laboratories have tested a total of 41,034 respiratory specimens for influenza viruses, and 7,361 (18%) were positive. Of the positive results, 7,338 (99.7%) were influenza type A and 23 (0.3%) were influenza type B. Of the 7,338 influenza A viruses, 1,665 (23%) have been subtyped and 1,659 (99.6%) were A(H3N2) and 6 (0.4%) were A(H1N1).
Antigenic Characterization of Viral Isolates: CDC has antigenically characterized 179 influenza viruses received from U.S. laboratories since October 1. Of the 172 influenza A(H3N2) viruses tested, 158 (92%) were similar to the vaccine strain A/Sydney/05/97 and 14 (8%) showed somewhat reduced titers to ferret antisera produced against A/Sydney/05/97. All 4 of the influenza B viruses antigenically characterized were similar to B/Beijing/184/93, which is represented in the current vaccine by B/Yamanashi/166/98. Of the 3 influenza A(H1N1) viruses antigenically characterized, 2 were similar to A/Beijing/262/95, the H1N1 component of the current vaccine, while 1 was more closely related to the antigenic variant A/New Caledonia/20/99.
Pneumonia and Influenza Mortality*: During week 2, the proportion of deaths due to pneumonia and influenza as reported by the vital statistics offices of 122 U.S. cities was 10.5%. This percentage is above the epidemic threshold of 7.4% for week 2 and is unusually high. The percentage of pneumonia and influenza deaths has exceeded threshold values for this time of year for 16 of the past 17 weeks. Whether this increase in the percentage of pneumonia and influenza deaths is due to influenza activity, respiratory illness due to some other pathogen, or reporting changes under way in the 122 Cities Mortality Reporting System is unknown. However, because these changes include a revision of the reporting case definition, the current increase in pneumonia and influenza mortality should be interpreted with caution.
From WHO:
During the months of October and November, sporadic isolations of influenza A and/or influenza B viruses were reported in Belgium, Bulgaria, Canada, China, Czech Republic, Denmark, Egypt, Finland, France, Germany, Iceland, Israel, Jamaica, Japan, Norway, Netherlands, Portugal, Sweden, Switzerland, UK and USA. In the southern hemisphere, Brazil reported local outbreak in Sao Paulo during the first week of October, while Argentina reports were mainly sporadic activity. Sporadic isolations of influenza A are still being reported in Brazil up to early December. Other countries; Australia, Chile, Malaysia, South Africa and Thailand reported sporadic isolations of influenza A and/or influenza B during the month of October, some up to December. In the northern hemisphere, influenza activity was still at baseline levels during October and November, although some States in the US have already reported regional activity. Canada also reported local outbreaks in November. The first sign of epidemic activity in Europe was during the first week of December, in south of France where a regional outbreak of influenza A occurred. Local outbreaks of influenza A were likewise reported in Finland, Ireland and UK during the same week. Influenza activity intensified to widespread or regional level from the second week of December up to the second week of January in Belgium, Canada, Finland, France, Germany, Iceland, Ireland, Italy, Netherlands, Norway, Spain, Sweden, Switzerland, UK and USA. During those weeks, local outbreaks were also reported in Czech Republic, Denmark and Slovak Republic. Epidemic level of influenza activity in Latvia started on the first week of January. Israel reported local outbreaks of influenza A(H3N2) during the third week of December, while Hungary noted significant increase in the frequency of influenza-like illness during the same month. During November and December, there were reports of influenza-like illness outbreaks in Iran. Influenza A(H3N2) viruses were isolated. Influenza activity has remained low in Austria, Bulgaria, Croatia, Greece, Portugal, Russian Federation and Yugoslavia, Federal Republic of. No influenza activity has been reported in Albania, Belarus, and Romania. Sporadic isolations of influenza A and/or B viruses continued to be reported in Australia, Hong Kong SAR of China, India, Malaysia, Senegal, South Africa and Thailand. Although influenza activity remains at its peak, since the second week of January, influenza-like illness consultations have started to decline in Belgium, France, Denmark and Norway. Influenza activity has again risen slightly in England but declined in Wales and Scotland. Of the total 15'651 influenza viruses isolated and reported to FluNet since 1 October, 79.7% were influenza A non-subtyped, 19.0% subtype A(H3N2), 0.1% subtype A(H1N1) and 1.2% influenza B.
Africa: From 1 October, 3 countries reported: Egypt, Senegal and South Africa. Influenza A and B cases were reported in these countries in October and November. Influenza A(H1N1) viruses were isolated in South Africa between October and December.
Americas: From 1 October, 6 countries reported: Argentina, Brazil, Canada, Chile, Jamaica and USA. A local outbreak was reported in Brazil during the first week of October with an isolate of influenza B. Since then, no influenza activity has been detected in South America. Few States in the US have reported regional activity since early part of the season. Canada reported local outbreaks during November but activity is still limited. Jamaica has not detected any influenza activity so far. Influenza activity in Canada and the US has intensified to widespread or regional level from the second week of December and has been continuing for the past three to four weeks. Overall, most viruses isolated were influenza A, some of which identified as subtype A(H3N2).
Asia: From 1 October, 7 countries reported: China, Hong Kong SAR of China, India, Iran, Japan, Malaysia and Thailand. Sporadic isolations of influenza A, A(H3N2) viruses were reported except India where no influenza activity has been detected. China also reported an influenza B virus isolate in November. Influenza viruses isolated in Thailand were mostly from sick children, however, virus type and subtype were not reported so far. Local outbreaks of influenza-like illness were reported during November and December in Iran, two influenza A viruses were isolated and identified as A(H3N2) subtype. Hong Kong SAR of China has reported an increase in influenza virus isolates, A(H3N2) and B, since the beginning of January.
Europe: From 1 October, 28 countries reported: Austria, Belarus, Belgium, Bulgaria, Croatia, Czech Republic, Denmark, Federal Republic of Yugoslavia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Israel, Italy, Latvia, Netherlands, Norway, Poland, Portugal, Romania, Slovak Republic, Spain, Sweden, Switzerland and United Kingdom. Of these countries, influenza viruses were isolated sporadically between October and November in; Belgium, Czech Republic, France, Finland, Denmark, Germany, Iceland, Ireland, Netherlands, Norway, Portugal, Sweden, Switzerland and UK. Latvia reported antigen detection of influenza A during the last week of November, its first case for the season. Almost all viruses isolated were influenza A, some were identified as subtype A(H3N2). The first influenza B case was reported in Sweden, diagnosed through antigen detection, while the first case of influenza A(H1N1) was detected in Caen, France. Outbreaks of influenza A were initially reported in Ireland and south of France, Rhone-Alpes region during the first week of December. Activity has intensified to widespread or regional level from the second week of December up to the first week of January in Belgium, Finland, France, Iceland, Ireland, Italy, Netherlands, Norway, Spain, Sweden, Switzerland and UK. Sporadic laboratory confirmed cases of influenza B were also reported. During the same weeks, local outbreaks were likewise being reported in Czech Republic, Denmark and Slovak Republic. Israel reported local outbreak of influenza A(H3N2) during the third week of December, while Hungary noted significant increase in the frequency of influenza-like illness during the same month. Influenza activity in the following countries remains at low level; Austria, Bulgaria, Croatia, Russian Federation and Yugoslavia,Federal Republic of. No influenza activity has been detected in Albania, Belarus and Romania since October. Influenza A(H3N2) virus is by far the predominant subtype. Although influenza activity remains at its peak, since the second week of January, influenza-like illness consultations have started to decline in Belgium, France, Denmark and Norway. Influenza activity has again risen slightly in England but declined in Wales and Scotland.
Current situation can be viewed at FluNet . The recommended vaccine for the current epidemic by WHO can be viewed at
This has also been highlighted by Prof.Lam Sai Kit's article in this issue.(Influenza in the World)
With that I let your "mouse" or your "keyboard" do the "talking".
Till next month, "Happy Surfing".
The links to URL mentioned above are valid at the time of writing (26 January 2000).
This page can be accessed at http://www.vadscorner.com/internet35.html or at http://www.vadscorner.com/mma_internet.html.