Influenza Global Epidemiologic Update
rd
Highlights of the situation as of October 3 , 2016
SUMMARY – WEEK 38 report (BASED ON DATA UP TO 18 SEPTEMBER 2016)
(1)
Influenza activity varied in countries of temperate South America, it was ongoing in South Africa and it decreased in Oceania.
Influenza activity in the temperate zone of the northern hemisphere was at inter-seasonal levels.
 In temperate South America, influenza and respiratory syncytial virus (RSV) activity decreased throughout most of the sub-region.
In Chile, influenza-like illness (ILI) and laboratory confirmed influenza and RSV virus detections remained elevated; influenza
A(H1N1)pdm09 was predominant with co-circulation of A(H3N2)viruses and influenza B viruses. In Paraguay, ILI and severe acute
respiratory infection (SARI) cases remained elevated. Respiratory syncytial virus activity remained elevated in the region.
 In South Africa, influenza detections continued, with mainly influenza A(H1N1)pdm09 virus detections following a predominance
of influenza B and then A(H3N2) viruses earlier in the season.
 In Oceania, influenza virus activity decreased in the last weeks. Influenza A(H3N2) remained the dominant circulating influenza
virus. In Australia, activity decreased but was still high, while in New Zealand ILI consultation rates remained below the seasonal
baseline level.
 In the Caribbean countries, influenza and other respiratory virus activity remained low throughout most of the sub-region. The
exception was Cuba with a slight increase of influenza B virus detections in the recent weeks. In Central America, influenza virus
activity remained low but in most of the countries, detections of non-influenza respiratory viruses stayed elevated with RSV
predominating.
 In tropical South America, influenza A(H1N1)pdm09 and RSV virus detections generally decreased in recent weeks or remained low
in most of the countries. In Colombia, influenza activity remained low while RSV activity increased. In Peru, influenza activity
continued to decrease, with influenza A(H1N1)pdm09 and influenza B viruses co-circulating.
 In West, Central and temperate East Asia, influenza activity remained low. In tropical countries of South Asia, influenza activity was
generally low with seasonal influenza A and B viruses co-circulating in the region.
 In South East Asia, there was a decreasing trend in influenza detection in recent weeks, although some countries in the region
reported ongoing activity of co-circulating seasonal influenza A and B viruses.
 Sporadic cases of influenza A(H3N2) and influenza B virus infection were reported by northern, middle and western Africa in
recent weeks, among the few countries reporting data during this period. In East Africa, Madagascar continued to report influenza
B detections.
 In North America and Europe, influenza activity was low with few influenza virus detections. ILI levels were below seasonal
thresholds. In the United States, other respiratory virus activity increased with RSV predominating.
 Influenza activity was low in temperate Asia.
 In the United States, seven human infections with novel influenza A viruses were reported by two states (Michigan and Ohio)
during week 33. No additional human infections with novel influenza A viruses were reported to CDC during week 38.
 WHO consultation and Information Meeting on the Composition of Influenza Virus Vaccines for Use in the 2017 Southern
Hemisphere influenza season was held on 26-28 September 2016 in Geneva. It is recommended that trivalent vaccines for use in
the 2017 southern hemisphere influenza season contain the following:
-
An A/Michigan/45/2015 (H1N1)pdm09-like virus;
-
An A/Hong Kong/4801/2014 (H3N2)-like virus; and
-
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.
Prepared by Sophie Druelles, VIE Influenza, Global Epidemiology Department
[email protected]
TABLE OF CONTENTS
1. SEASONAL INFLUENZA EPIDEMIOLOGICAL UPDATE ......................................... 3
1.1 Global circulation of Influenza (1)................................................................................. 3
1.2 Countries in the temperate zone of the northern hemisphere (1, 3, 11, 12,13) ..................... 4
North America ................................................................................................................ 4
Europe(11) ........................................................................................................................ 5
Western Asia................................................................................................................... 6
Central Asia .................................................................................................................... 6
Northern Temperate Asia ............................................................................................... 6
1.3 Countries in the tropical zone ....................................................................................... 6
Tropical countries of the Americas/Central America and the Caribbean(1, 3) ................. 6
African region(1).............................................................................................................. 7
Tropical Asia(1) ............................................................................................................... 7
1.4 Countries in the temperate zone of the southern hemisphere ....................................... 7
Temperate South America (1,3) ........................................................................................ 8
Southern Africa(1) ........................................................................................................... 8
2. VIROLOGICAL SURVEILLANCE (1) ........................................................................... 10
3. SOURCES ....................................................................................................................... 12
Influenza Global Epidemiologic Update
Highlights of the situation as of october 5th, 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 october 5th, 2016
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1.2 Countries in the temperate zone of the northern hemisphere (1, 3, 11, 12,13)
North America
Overall influenza and other respiratory virus activity remained low. Except in the United States,
RSV (9.8% percent positivity) and other respiratory virus activity increased with RSV
predominating, while influenza remained low (1.82% percent positivity).
United States:
During EW 37, influenza activity remained low (1.8%), with influenza A predominating (54.17% of
all influenza-positive detections).
Pneumonia and influenza mortality slightly decreased and remained low (5.2%) and below the
epidemic threshold (5.8%) for EW 37
During EW 37, national ILI activity slightly increased (1.1%) and remained below the national
baseline of 2.1%. ILI activity was reported to be similar to previous seasons for the same time of
year.
Canada:
In week 38, influenza activity is at inter-seasonal levels with the majority regions of Canada
reporting low or no influenza activity. Localized activity was reported in three regions across three
provinces (BC, AB, and ON).
A total of 73 positive influenza detections were reported in weeks 37 and 38; influenza A(H3N2)
was the most common subtype detected. In week 38, 1% of visits to sentinel healthcare
professionals were due to ILI.
The first laboratory-confirmed influenza outbreak this season was reported in week 37. A total
of five outbreaks were reported in weeks 37 and 38.
Influenza Global Epidemiologic Update
Highlights of the situation as of october 5th, 2016
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Europe(11)
Week 20 was the last weekly bulletin of the 2015–2016 influenza season in Europe. Weekly online reporting
for the next season will start in week 40/2016. During summer months, weekly reporting to the European
Surveillance System (TESSy) will continue, but bulletins will be issued monthly: on 1 July, 5 August, 9
September and 7 October.
For weeks 31–35/2016, 23–30 countries reported weekly epidemiological data. All reported lowintensity influenza activity. Of the 30 countries or regions that reported on geographical spread,
one (Armenia) reported local activity during four weeks of the reporting period; three (Azerbaijan,
Lithuania and the United Kingdom (Scotland)) reported sporadic activity throughout the reporting
period; five (Croatia, Norway, Slovakia, Tajikistan and the United 2 Kingdom (Northern Ireland))
reported sporadic activity for at least one week and the remaining countries reported no influenza
activity during the period.
Among the 23 countries that reported on trends in influenza activity, five (Armenia, Azerbaijan,
Lithuania, the Russian Federation and Ukraine) noted slightly increasing consultation rates for
influenza-like illness (ILI) and/or acute respiratory infection (ARI) and 18 reported decreasing or
stable trends.
Influenza Global Epidemiologic Update
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Northern Africa and Western Asia
Influenza virus detections, of predominantly influenza A(H3N2), remained low in the countries
reporting data during this period.
Central Asia
Northern Temperate Asia
In Northern Temperate Asia, influenza activity continued at low levels with both influenza A and B
viruses detected in the region.
1.3 Countries in the tropical zone
Tropical countries of the Americas/Central America and the Caribbean(1, 3)
In the Caribbean, low influenza and other respiratory virus activity were reported throughout most
of the sub-region, except in Cuba where a slight increase in activity of influenza B was reported.
Most epidemiological indicators remained low or decreasing.
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In Central America, low influenza activity was reported, but RSV circulation remained active in
Costa Rica and Nicaragua with a slight increase in influenza B activity. Most epidemiological
indicators remained low or decreasing.
African region(1)
Sporadic cases of influenza A(H3N2) and influenza B virus infection were reported by northern,
middle and western Africa in recent weeks, among the few countries reporting data during this
period. In East Africa, Madagascar continued to report influenza B detections.
Tropical Asia(1)
Overall, influenza activity in Southern Asia was low with both influenza A and influenza B viruses
circulating.
Nepal reported decreased detection of influenza A(H3N2) and B viruses. In Southeast Asia, there
was a decreasing trend in influenza detection in recent weeks, with influenza A(H1N1)pdm09,
A(H3N2) and influenza B viruses co-circulating. Singapore, where predominantly influenza A(H3N2)
virus circulated, reported decreased detections in the last few weeks. Cambodia continued to
report an increase in influenza B detections. Thailand reported predominantly increased
detections of influenza A(H1N1)pdm09 and A(H3N2), with additional circulating B viruses. The
majority of detections in Malaysia and the Philippines were due to B viruses, with co-circulating
A(H1N1)pdm09 and A(H3N2) viruses, whereas the majority of detections in Laos PDR were due to
A(H1N1)pdm09, co-circulating with A(H3N2) and B viruses.
Focus on Singapore (5)
Weekly infectious disease bulletin – EW 38 – 18-24 September 2016
Influenza indicators for E-week 38 (18 - 24 Sep 2016) are as follows:
 The average daily number of patients seeking treatment in the polyclinics for ARI decreased from 2,566 (over 4.5 working days) in E-week 37 to
2,449 (over 5.5 working days) in E-week 38.
 The proportion of patients with influenza-like illness (ILI) among the polyclinic attendances for ARI remained low at 1.6%. The overall positivity
rate for influenza among ILI samples (n=128) in the community was 33.6% in the past 4 weeks. Of the specimens tested positive for influenza in
August 2016, these were positive for influenza A(H3N2) (85.0%), influenza B (13.1%) and influenza A (H1N1)pdm09 (1.9%).
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1.4 Countries in the temperate zone of the southern hemisphere
Temperate South America
(1,3)
In Brazil and in the Southern Cone, influenza and RSV levels trended downward throughout most
of the sub-region, except in Chile where influenza activity remained elevated. ILI activity remained
elevated in Chile and Paraguay, while SARI-related ICU admissions slightly increased in Uruguay.
In the Andean sub-region, influenza and other respiratory virus activity remained low overall.
Southern Africa(1)
In South Africa, influenza detections continued, with mainly influenza A(H1N1)pdm09 virus
detections following a predominance of influenza B and then A(H3N2) viruses earlier in the
season.
Focus on South Africa(6)
National Institute for communicable diseases
Weekly influenza and respiratory syncytial surveillance report, week 31, 2016
In 2016 to date, specimens from 711 patients were received from Viral Watch sites. Influenza A not subtyped was detected in
one patient, influenza A(H1N1)pdm09 in 24, influenza A(H3N2) in 92, and influenza B in 176 patients. Pneumonia
surveillance: In this time
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Oceania, Melanesia and Polynesia(1)
In Oceania, influenza virus activity appeared to have peaked. In recent weeks, influenza activity
decreased nationally in Australia but was still widespread in several regions. Influenza A(H3N2)
remained the dominant circulating influenza virus. In this season the rates have been highest in
the elderly aged 75 years and older, with a secondary peak in the very young. New Zealand
continued to see levels of ILI activity below the seasonal baseline level. New Caledonia continued
to have decreased activity. From the Pacific Islands, Guam, Marshall Islands, Samoa and Tonga
reported influenza activity.
Focus on New Zealand(7)
Community and Hospital Surveillance ILI, SARI, Influenza and Respiratory Pathogens 2016 Influenza Season,
Week 38, ending 25 September 2016
During week 38 (19–25 September 2016), influenza activity was very low among consultation-seeking patients
nationwide. Influenza activity was also low among those hospitalised patients in Auckland and Counties Manukau District
Health Boards.
 ILI surveillance: Forty-eight patients with influenza-like illness consulted sentinel general practices in 20 DHBs. The
weekly ILI incidence was 8.9 per 100 000 patient population (Figure 1), below the seasonal threshold of ILI
consultations. The ILI related influenza incidence (adjusted) was 3.0 per 100 000 patient population.
 Influenza virus: During this week, 21 ILI specimens were tested, seven were positive for influenza viruses. In addition,
38 SARI specimens were tested, 13 were positive for influenza viruses. For details, see Table 3 and Figures 5 and 6.
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Focus on Australia(8)
Australian Government, Department of Health – 3 to 16 September 2016
 In the fortnight ending 16 September 2016, influenza activity declined nationally; however, widespread activity continued to be reported
in a number of regions.
 National indicators of influenza-like illness (ILI) declined in the last fortnight, further supporting that the season has peaked nationally.
The proportion of patients presenting to sentinel general practitioners with ILI and testing positive for influenza declined this fortnight. The
percentage of tests positive for influenza across all sentinel laboratories was 17.6% in week 37, a decrease from 20.6% in week 36;
continuing the decline from the peak in week 35 of 20.8% (Figure 2)
 Influenza A(H3N2) continued to be the dominant circulating influenza virus nationally.
 Notification rates this year to date have been highest in adults aged 75 years or older, with a secondary peak in the very young,
aged less than 5 years. This is consistent with influenza A(H3N2) being typically more prevalent in older age groups.
 Clinical severity for the season to date, as measured through the proportion of patients admitted directly to ICU and deaths attributable to
pneumonia or influenza, is low to moderate.
 To date, the seasonal influenza vaccines appear to be a good match for circulating virus strains.
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Highlights of the situation as of october 5th, 2016
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2. VIROLOGICAL SURVEILLANCE (1)
WHO Virus strain typing FluNet reporting (as of September, 30th 2016)
Influenza Type
A
B
From 5 to 18 September 2016
N (%)
Virus lineage sub-type N (%)*
2,260 (81.8%)
246 (12%) A(H1N1)pdm09
1,812 (88%) A(H3N2)
503 (18.2%)
31 (24.6%) B-Yamagata
95 (75.4%) B-Victoria
*Figures from National Influenza Centres (NICs) and other national influenza laboratories from 73
countries, areas or territories reported data. Among more than 44,178 specimens, 2,763 were
positive for influenza viruses (6.3%).
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3. 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/ and
http://www.who.int/influenza/resources/charts/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/content/moh_web/home/statistics/infectiousDiseasesStatistics/weekly_infectiousdiseases
bulletin.html
6. National Institute for communicable Disease of South Africa http://www.nicd.ac.za/?page=seasonal_influenza&id=72
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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