Influenza Global Epidemiologic Update
th
Highlights of the situation as of March 9 , 2016
SUMMARY – WEEK 08 report (BASED ON DATA UP TO 21 FEBRUARY 2016)
(1)
In the Northern hemisphere, high levels of influenza activity continued with influenza A(H1N1)pdm09 predominating. An
increase in the proportion of influenza B viruses has been detected. In the Southern Hemisphere and in tropical
countries, influenza activity was generally low.
 In Europe, ongoing high levels of influenza activity continued to be reported, although in some countries activity
seemed to have peaked already. Influenza A(H1N1)pdm09 accounted for most virus detections with an increase in the
proportion of influenza B detections. In Russian Federation and Ukraine, elevated SARI activity continued but at lower
levels compared to previous weeks.
 In North America, influenza activity increased further with influenza A(H1N1)pdm09 predominating in Canada and
United States of America. Influenza A(H3N2) predominated in Mexico.
 In northern/temperate Asia, influenza activity remained high but seemed to have peaked already in some countries.
 In Western Asia, influenza activity continued to decrease. Oman reported ongoing low levels of both influenza
A(H1N1)pdm09 and influenza B viruses.
 In Africa, influenza A(H1N1)pdm09 activity was reported in Northern Africa.
 In tropical countries of the Americas, Central America and the Caribbean, influenza and other respiratory virus activity
were overall at low levels in most countries, except in Jamaica and in Puerto Rico where high but decreasing influenza
activity has been reported.
 In South East Asia, ongoing low influenza activity was reported during this period.
 In the temperate countries of the southern hemisphere, respiratory virus activity remained low at inter-seasonal levels.
 The recommended composition of influenza virus vaccines for use in the 2016-2017 northern hemisphere influenza
season is presented at the end of the update.
Prepared by Sophie Druelles, VIE Influenza, Global Epidemiology Department
[email protected]
Influenza Global Epidemiologic Update
Highlights of the situation as of March 09th, 2016
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TABLE OF CONTENTS
1. SEASONAL INFLUENZA EPIDEMIOLOGICAL UPDATE ......................................... 4
1.1 Global circulation of Influenza (1)................................................................................. 4
1.2 Countries in the temperate zone of the northern hemisphere (1, 11, 12, 13) ....................... 5
North America ................................................................................................................ 5
Europe(11) ........................................................................................................................ 8
Western Asia................................................................................................................... 9
Central Asia .................................................................................................................... 9
Northern/Temperate Asia ............................................................................................... 9
1.3 Countries in the tropical zone ..................................................................................... 11
Tropical countries of the Americas/Central America and the Caribbean(1, 3) ............... 11
African region(1)............................................................................................................ 13
Tropical Asia(1) ............................................................................................................. 13
1.4 Countries in the temperate zone of the southern hemisphere ..................................... 14
Temperate South America (1,3) ...................................................................................... 15
Southern Africa(1) ......................................................................................................... 15
2. VIROLOGICAL SURVEILLANCE (1) ........................................................................... 16
3. RECOMMENDED COMPOSITION OF INFLUENZA VIRUS VACCINES FOR USE
IN THE 2016-2017 NORTHERN HEMISPHERE INFLUENZA SEASON ...................... 16
4. SOURCES ....................................................................................................................... 17
Influenza Global Epidemiologic Update
Highlights of the situation as of March 09th, 2016
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1. SEASONAL INFLUENZA EPIDEMIOLOGICAL UPDATE
1.1 Global circulation of Influenza (1)
Influenza Global Epidemiologic Update
Highlights of the situation as of March 09th, 2016
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1.2 Countries in the temperate zone of the northern hemisphere (1, 11, 12, 13)
North America
In North America, overall moderate levels of influenza and other respiratory activity were
reported.
In Canada (see focus), seasonal influenza activity, predominantly of influenza A(H1N1)pdm09,
continued to increase and spread geographically. Percent positivity increased to 29% which was
above expected levels. Influenza-like illness (ILI) also continued to increase with highest rate in
those 20-64 years of age. Young/middle age adults accounted for an increased proportion of
hospitalizations during this reporting period.
In the United States of America (see focus), influenza activity continued to increase. Influenza
A(H1N1)pdm09 accounted for most detections following by influenza A(H3N2) and then by
influenza B viruses. ILI activity increased and was reported to be 3.2% in week 8 which is above the
national baseline of 2.1%. Continued high level of respiratory syncytial virus (RSV) was reported.
Pneumonia and influenza mortality increased to 7.1% but was below epidemic threshold of 7.2%.
In Mexico, acute respiratory infections (ARI) continued to increase above expected levels for this
time of year with influenza A(H3N2) and influenza A(H1N1)pdm09 co-circulating.
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Focus on Canada(12)
Public Health Agency of Canada, 21 – 27 February 2016 (week 8)
 Overall, in week 08, influenza activity continued to increase; the percent positive for influenza increased from 29% in
week 07 to 33% in week 08.
 Influenza A(H1N1) remains the most common influenza subtype circulating in Canada.
 The Eastern provinces of Canada accounted for the majority of influenza laboratory confirmations. A total of 20 regions
across Canada reported sporadic influenza/ILI activity (see map).
 In week 08, adults 65+ years of age accounted for the largest proportion of hospitalizations.
 The number of outbreaks reported in week 08 increased sharply from the previous week (38 new laboratory confirmed
influenza outbreaks) with the majority of outbreaks reported in long-term facilities. To date this season, 176 outbreaks
have been reported.
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Focus on the United States(13)
US-CDC – Influenza Weekly Report- Week 8 ending February 27, 2016
Summary of Findings
 During week 8 (February 21-27, 2016), influenza activity remained elevated in the United States.
 The most frequently identified influenza virus type reported by public health laboratories during week 8 was influenza A
viruses, with influenza A(H1N1)pdm09 viruses predominating. The percentage of respiratory specimens testing positive for
influenza in clinical laboratories increased.
 Four influenza-associated pediatric deaths were reported.
 A cumulative rate for the season of 7.8 laboratory-confirmed influenza-associated hospitalizations per 100,000 population
was reported.
 The proportion of outpatient visits for influenza-like illness (ILI) was 3.2%, which is above the national baseline of 2.1%.
Nine (9) of 10 regions reported ILI at or above region-specific baseline levels. Puerto Rico and eight states experienced
high ILI activity. New York City and 9 states experienced moderate ILI activity; 13 states experienced low ILI activity; 20
states experienced minimal activity; and the District of Columbia and one state had insufficient data.
 The geographic spread of influenza during week 8 was as represented on the figure below (widespread activity was
reported by Puerto Rico and 33 states)
Virologic surveillance: The results of tests performed by clinical laboratories are summarized below:
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Europe(11)




For week 08, 25 of the 45 Member States in the WHO European region that uploaded
epidemiological data reported widespread influenza activity.
As only 5 countries reported high-intensity activity (Albania, Greece, Finland, Iceland and
Luxembourg), influenza may have peaked in some parts of the Region, as indicated by
reports of decreasing or stable trends in 33 countries.
36 countries reported influenza virus detections in 47% of specimens from sentinel
sources, which is similar to previous weeks. Influenza B constituted 47% of detections in
sentinel samples, compared to 43% for the previous week, indicating a gradual shift
towards influenza B. Influenza A(H1N1)pdm09 remained the predominant virus detected
through sentinel surveillance, accounting for 85% of the A viruses subtyped.
Most severe cases were associated with A(H1N1)pdm09 and were in people aged 15-64
years.
Season:


So far, a predominance of influenza A(H1N1)pdm09 viruses has characterized the 20152016 influenza season in most countries in the Region; this subtype may cause more
severe disease and deaths in people aged under 65 years than A(H3N2).
Most of the viruses characterized so far have been similar to those recommended for
inclusion in the trivalent or quadrivalent vaccines for this season in the northern
hemisphere.
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Virus characteristics: the trivalent vaccine that is used by most countries does not cover most of
the B viruses circulating. During week 8, B/Victoria lineage is predominating in Europe (300
B/Victoria vs 8 B/Yamagata in sentinel source).
Western Asia
In western Asia, in Bahrain, Jordan and Qatar, influenza activity continued to decrease as seen in
previous weeks. In Israel and Oman, sustained but slightly decreased levels of activity of influenza
A(H1N1)pdm09 with some circulating influenza B were reported.
Central Asia
Throughout Central Asia, ongoing but decreasing influenza activity associated with influenza
A(H1N1)pdm09 viruses was reported. SARI activity continued to be elevated in Kazakhstan.
Northern/Temperate Asia
In Northern/Temperate Asia, high levels of influenza activity were again reported in this region.
Influenza A(H1N1)pdm09 accounted for the majority of this activity, followed by a mix of influenza
A(H3) and influenza B viruses. In Mongolia, influenza B virus predominated during this period.
Increasing influenza activity, mostly of influenza A(H1N1)pdm09, continued to be detected in the
Republic of Korea with some influenza B virus circulating. ILI activity slightly decreased during this
period but was above national baseline overall.
In northern China (see focus), influenza activity continued to be on the decline, with both influenza
A and B viruses co-circulating.
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Focus on China(2)
CDC-China – Influenza Weekly Report- Week 8/2016
Summary of Findings
 During week 8, influenza activity in mainland China was at the level of flu season with influenza A(H1N1)pdm09,
A(H3N2) and B viruses co-circulating. The detection positive rate of influenza B was higher than influenza A.
 During week 8, there were 11 outbreaks reported nationwide.
 During week 8, the percentage of outpatient or emergency visits for ILI (ILI %) at national sentinel hospitals in
south China was 3.0%, the same as last week.
 During week 8, ILI% at national sentinel hospitals in north China was 3.5%, lower than the week before (3.6%)
Virologic surveillance for week 8
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1.3 Countries in the tropical zone
Tropical countries of the Americas/Central America and the Caribbean(1, 3)
Tropical countries of South America continued to report low and within expected levels of
influenza and other respiratory virus activity.
Ecuador reported high respiratory syncytial virus (RSV) activity with an increasing trend.
Overall in Central America and the Caribbean, decreasing and low levels of influenza and other
respiratory virus activity were reported.
In Jamaica, increasing detections of influenza A(H1N1)pdm09 viruses were reported and SARI
activity remained high compared to previous years.
A high level of activity was reported in Puerto Rico.
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(3)
Influenza virus circulation by region, 2012-2016
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African region(1)
Overall, the African region reported low levels of influenza activity. The exception was northern
Africa (Algeria, Morocco and Niger) where increasing influenza A(H1N1)pdm09 activity was
reported during this period.
Tropical Asia(1)
As seen in previous weeks in southern China, influenza A(H1N1)pdm09 remained high and
predominant.
In Hong Kong (see focus), an increase in the co-circulation of influenza A(H1N1)pdm09 and
influenza B viruses was detected. ILI activity in general outpatient clinics and sentinel private
doctors was higher during this reporting period compared to recent weeks.
In South East Asia (Cambodia and Singapore), ongoing influenza activity was reported with a mix of
influenza A and B viruses co-circulating.
In Thailand, influenza activity increased with influenza B virus predominating.
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Focus on Hong Kong(4)
Hong Kong - Flu Express February 21-27, 2016 (Week 9) – Summary
 The latest surveillance data showed that the overall influenza activity has continued to increase. It is expected that the influenza activity will
remain at a high level in the coming weeks.
 The Centre for Health Protection (CHP) has collaborated with the Hospital Authority (HA) and private hospitals to reactivate the enhanced
surveillance for severe seasonal influenza cases among patients aged 18 or above since January 29, 2016. As of Mar 2, 154 adult severe cases
(including 49 deaths) were recorded. Separately, 10 cases of severe paediatric influenza-associated complications among patients aged below
18 (including one death) were recorded during the period.
 In week 9, the average consultation rate for influenza-like illness (ILI) among sentinel general outpatient clinics (GOPCs) was 9.5 ILI cases per
1,000 consultations, which was higher than 9.0 recorded in the previous week.
 Among the respiratory specimens received in week 9, 1286 (25.93%) were tested positive for seasonal influenza viruses, including 840 (16.94%)
influenza A(H1), 57 (1.15%) influenza A(H3), 357 (7.2%) influenza B and 32 (0.65%) influenza C.
 In week 9, 58 ILI outbreaks occurring in schools/institutions (affecting 421 persons) were recorded, as compared to 6 outbreaks (affecting 67
persons) recorded in the previous week.
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1.4 Countries in the temperate zone of the southern hemisphere
Temperate South America
(1,3)
In temperate South America, influenza and other respiratory virus activity continued to remain
low. SARI levels also remained at low and below expected levels.
In Chile, ILI activity slightly increased but remained within expected levels. Influenza activity was
low.
SARI levels were slightly elevated in Argentina and Paraguay.
(1)
Southern Africa
Inter-seasonal levels of influenza activity continue to be reported in South Africa.
Oceania, Melanesia and Polynesia(1)
Australia continued to report minimal influenza A(H1N1)pdm09 activity. In the Pacific Islands,
Micronesia (Federal States of) reported above threshold levels of ILI activity.
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2. VIROLOGICAL SURVEILLANCE (1)
WHO Virus strain typing FluNet reporting (as of 04 March 2016)
Influenza Type
A
B
From 08 February to 21 February 2016
N (%)
Virus lineage sub-type N (%)*
19,269 (87.7%) A(H1N1)pdm09
33,745 (79%)
2,709 (12.3%) A(H3N2)
589 (24.4%) B-Yamagata
8,982 (21%)
1,821 (75.6%) B-Victoria
*Figures from National Influenza Centres (NICs) and other national influenza laboratories from 98
countries, areas or territories reported data. Among more than 158,158 specimens, 42,727 were
positive for influenza viruses (27.0%).
3. RECOMMENDED COMPOSITION OF INFLUENZA VIRUS VACCINES FOR USE IN THE
2016-2017 NORTHERN HEMISPHERE INFLUENZA SEASON
It is recommended that trivalent vaccines for use in the 2016-2017 northern hemisphere influenza
season contain the following:
- an A/California/7/2009 (H1N1)pdm09-like virus;
- an A/Hong Kong/4801/2014 (H3N2)-like virus;
- a B/Brisbane/60/2008-like virus.
It is recommended that quadrivalent vaccines containing two influenza B viruses contain the
above three viruses and a B/Phuket/3073/2013-like virus.
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4. SOURCES
1. WHO Influenza Update
http://www.who.int/influenza/surveillance_monitoring/updates/latest_update_GIP_surveillance/en/ and
http://www.who.int/influenza/gisrs_laboratory/updates/summaryreport/en/
2. Chinese National Influenza Center – Influenza Weekly Report- Week http://www.cnic.org.cn/
3. Pan-American Health Organization (PAHO) Regional Update
http://www.paho.org/hq/index.php?option=com_content&view=article&id=3352&Itemid=2469&to=2246&lang=es
4. Hong Kong Centre for Health Protection- Flux Express Surveillance Report
http://www.chp.gov.hk/en/guideline1_year/134/441/304.html
5. Singapore Ministry of Health - WEEKLY INFECTIOUS DISEASE BULLETIN - https://www.moh.gov.sg/
6. National Institute for communicable Disease of South Africa - Influenza Surveillance Report compiled 03 Sept 2015
http://www.nicd.ac.za
7. New Zealand: Influenza Weekly Update https://surv.esr.cri.nz/virology/influenza_weekly_update.php
8. Australian Government - Department of Health - Influenza Surveillance Report
http://www.health.gov.au/internet/main/publishing.nsf/content/cda-surveil-ozflu-flucurr.htm
9. Argentina, Boletin Integrado de Vigilancia, http://www.msal.gob.ar/index.php/home/boletin-integrado-de-vigilancia
10. Weekly influenza update of the Brazilian Ministry of health (in Portuguese)
http://portalsaude.saude.gov.br/index.php/situacao-epidemiologica-dados-influenza
11. ECDC/ WHO Europe Weekly Influenza update – http://flunewseurope.org/
12. Government of Canada, FluWatch Report http://healthycanadians.gc.ca/diseases-conditions-maladiesaffections/disease-maladie/flu-grippe/surveillance/fluwatch-reports-rapports-surveillance-influenza-eng.php
13. Centers for Disease Control and Prevention, Weekly U.S. Influenza Surveillance Report
http://www.cdc.gov/flu/weekly/
14. WHO NIC at Research Institute of Influenza and D.I Ivanovsky Institute of Virology, Integrated data of influenza
morbidity and diagnosis
http://www.influenza.spb.ru/en/influenza_surveillance_system_in_russia/epidemic_situation/
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