FluWatch report: January 23, 2022 to January 29, 2022 (week 4)

On this page

• Influenza/Influenza-like Illness Activity - Geographic Spread
• Laboratory-Confirmed Influenza Detections
• Syndromic / Influenza-like Illness Surveillance
• Influenza Outbreak Surveillance
• Influenza Severe Outcomes Surveillance
• Influenza Strain Characterization
• Antiviral Resistance
• Influenza Vaccine Monitoring
• Provincial and International Influenza Reports

Influenza/Influenza-like Illness Activity - Geographic Spread

In week 04, eight regions in six provinces (B.C., Alta., Sask., Man., Ont., and Que.) reported sporadic influenza/ILI activity. All other surveillance regions reported no influenza/ILI activity (Figure 1).

Number of Regions Reporting in Week 04: 53 out of 53

Figure 1 - Text description

Province	Influenza Surveillance Region	Activity Level
N.L.	Eastern	No Activity
N.L.	Labrador-Grenfell	No Activity
N.L.	Central	No Activity
N.L.	Western	No Activity
P.E.I.	Prince Edward Island	No Activity
N.S.	Zone 1 - Western	No Activity
N.S.	Zone 2 - Northern	No Activity
N.S.	Zone 3 - Eastern	No Activity
N.S.	Zone 4 - Central	No Activity
N.B.	Region 1	No Activity
N.B.	Region 2	No Activity
N.B.	Region 3	No Activity
N.B.	Region 4	No Activity
N.B.	Region 5	No Activity
N.B.	Region 6	No Activity
N.B.	Region 7	No Activity
Que.	Nord-est	Sporadic
Que.	Québec et Chaudieres-Appalaches	No Activity
Que.	Centre-du-Québec	No Activity
Que.	Montréal et Laval	Sporadic
Que.	Ouest-du-Québec	No Activity
Que.	Montérégie	No Activity
Ont.	Central East	No Activity
Ont.	Central West	No Activity
Ont.	Eastern	No Activity
Ont.	North East	No Activity
Ont.	North West	Sporadic
Ont.	South West	No Activity
Ont.	Toronto	No Activity
Man.	Northern Regional	No Activity
Man.	Prairie Mountain	No Activity
Man.	Interlake-Eastern	No Activity
Man.	Winnipeg	No Activity
Man.	Southern Health	Sporadic
Sask.	North	No Activity
Sask.	Central	No Activity
Sask.	South	Sporadic
Alta.	North Zone	No Activity
Alta.	Edmonton	No Activity
Alta.	Central Zone	No Activity
Alta.	Calgary	No Activity
Alta.	South Zone	Sporadic
B.C.	Interior	Sporadic
B.C.	Fraser	Sporadic
B.C.	Vancouver Coastal	No Activity
B.C.	Vancouver Island	No Activity
B.C.	Northern	No Activity
Y.T.	Yukon	No Activity
N.W.T.	North	No Activity
N.W.T.	South	No Activity
Nvt.	Qikiqtaaluk	No Activity
Nvt.	Kivalliq	No Activity
Nvt.	Kitimeot	No Activity

Laboratory-Confirmed Influenza Detections

In week 04, 8 laboratory detections of influenza A were reported. The number of weekly detections and percentage of tests positive for influenza has decreased since the end of the December.

Overall, the percentage of laboratory tests positive for influenza remains at exceptionally low levels, despite the elevated levels of testing. In week 04, 16,004 tests for influenza were performed at reporting laboratories and the percentage of tests positive for influenza was 0.05%. Compared to the past six pre-pandemic seasons (2014-2015 to 2019-2020), an average of 11,441 tests were performed for this time period, with an average of 24.0% of tests positive for influenza (Figure 3).

To date this season (August 29, 2021 to January 29, 2022), 494 influenza detections (382 influenza A and 112 influenza B) have been reported, which is lower than what we have seen historically in the past six pre-pandemic seasons, where an average of 21,145 influenza detections were reported at this point in the season. Among subtyped influenza A detections (110), influenza A(H3N2) accounted for 93% of detections.

Detailed information on age and type/subtype has been received for 386 laboratory-confirmed influenza detections (Figure 4). Among the 391 detections, 322 (82%) were in individuals under the age of 45.

Testing for influenza and other respiratory viruses has been influenced by the current COVID-19 pandemic. Changes in laboratory testing practices may affect the comparability of data to previous weeks or previous seasons.

For more detailed weekly and cumulative influenza data, see the text descriptions for Figures 2 and 3 or the Respiratory Virus Detections in Canada Report.

Number of Laboratories Reporting in Week 4: 31 out of 34

For one province, only data from subtyped influenza A specimens are included in the weekly number of positive influenza tests in Figure 2. The number of positive tests reported in Figure 2 may not equal the total number of positive tests in the report body text.

Figure 2 - Text description

Surveillance Week	A(Unsubtyped)	A(H3N2)	A(H1N1)	Influenza B	Percent Positive A	Percent Positive B
35	3	0	0	0	0.0	0.0
36	1	0	0	0	0.0	0.0
37	1	3	0	0	0.0	0.0
38	0	0	0	0	0.0	0.0
39	0	0	1	0	0.0	0.0
40	0	0	0	2	0.0	0.0
41	2	1	0	3	0.0	0.0
42	0	1	1	2	0.0	0.0
43	2	1	0	3	0.0	0.0
44	1	2	0	16	0.1	0.1
45	2	9	0	10	0.1	0.1
46	3	8	0	9	0.1	0.1
47	4	11	0	12	0.2	0.1
48	11	7	0	28	0.2	0.2
49	29	6	0	9	0.2	0.1
50	19	12	1	4	0.3	0.0
51	25	12	1	6	0.2	0.0
52	10	12	1	2	0.1	0.0
1	10	11	1	1	0.1	0.0
2	16	2	2	3	0.1	0.0
3	4	2	0	2	0.0	0.0
4	4	2	0	0	0.1	0.0

The shaded area represents the maximum and minimum number of influenza tests or percentage of tests positive reported by week from seasons 2014-2015 to 2019-2020. Data from week 11 of the 2019-2020 season onwards are excluded from the historical comparison due to the COVID-19 pandemic.

Included in the cumulative detections this season are 11 co-infections of influenza A and B (total of 22 detections) that were suspected to be associated with live attenuated influenza vaccine (LAIV) receipt. Beginning in week 44 co-infections known or reported to be associated with recent LAIV were removed by the submitting laboratory or by the Public Health Agency of Canada as they do not represent community transmission of seasonal influenza viruses.

Figure 3 - Text description

a) Number of influenza tests, 2021-2022 compared to previous seasons

Surveillance Week	Number of Tests, 2021-2022	Number of Tests, 2020-2021	Maximum Number of Tests	Minimum Number of Tests	Average Number of Tests
35	7140	4996	1979	1311	1705
36	8012	5192	2208	1323	1707
37	9317	5335	2631	1778	2135
38	9821	6024	3039	1987	2502
39	9691	6707	3356	2365	2859
40	10776	7127	4078	2443	3134
41	10372	6817	4339	2673	3240
42	12508	6755	4649	2648	3526
43	13341	8227	4996	3084	3862
44	15442	9615	4966	2994	4020
45	17547	10748	5912	3117	4508
46	16418	11955	5589	3176	4564
47	16923	13103	6541	3587	5018
48	18532	18762	7416	3569	5645
49	19974	19649	8559	3836	6377
50	22549	16189	9464	4017	7155
51	28471	14059	11142	3487	8822
52	29557	12290	11338	4272	9184
1	28419	11681	14932	5371	12552
2	23658	14097	16104	5315	13289
3	19585	17002	15001	5270	11820
4	16004	15391	15414	5873	11441
5	N/A	16607	16595	6739	11456
6	N/A	12949	16121	8324	11339
7	N/A	20727	14443	8074	10842
8	N/A	21290	14024	7606	10865
9	N/A	21891	14520	7507	10956
10	N/A	20896	17681	7005	11084
11	N/A	21220	12714	6435	9175
12	N/A	23087	10431	5976	8238
13	N/A	25811	9989	6063	7699
14	N/A	26303	8830	4773	7046
15	N/A	26284	7836	5090	6527
16	N/A	26792	6826	5000	5890
17	N/A	29154	6603	4440	5305
18	N/A	22152	5640	4143	4780
19	N/A	12725	5480	3680	4311
20	N/A	9738	5097	3046	3862
21	N/A	7442	4001	2577	3197
22	N/A	6765	3790	2424	2944
23	N/A	6341	3257	1969	2591
24	N/A	5942	3120	2034	2449
25	N/A	5774	2659	1731	2148
26	N/A	5972	2600	1573	1988
27	N/A	5213	2163	1554	1833
28	N/A	4900	2223	1451	1857
29	N/A	5122	2256	1436	1796
30	N/A	5275	1950	1463	1664
31	N/A	5398	2022	1386	1671
32	N/A	4692	1928	1269	1574
33	N/A	5616	2089	1251	1671
34	N/A	5851	2098	1374	1698

b) Percentage of tests positive for influenza, 2021-2022 compared to previous seasons

Surveillance Week	Percentage of tests positive, 2021-2022	Percentage of tests positive, 2020-2021	Maximum Percentage of Tests Positive	Minimum Percentage of Tests Positive	Average Percentage of Tests Positive
35	0.04	0.02	1.87	0.11	0.82
36	0.01	0.00	2.28	0.30	1.13
37	0.04	0.00	1.78	0.40	0.99
38	0.00	0.02	2.35	0.55	1.30
39	0.01	0.00	2.95	0.67	1.71
40	0.02	0.00	2.33	1.08	1.70
41	0.06	0.01	3.02	1.32	1.72
42	0.05	0.00	3.40	0.87	2.18
43	0.05	0.01	5.32	0.84	2.83
44	0.21	0.07	8.55	1.20	3.70
45	0.14	0.04	10.10	1.39	4.63
46	0.16	0.03	14.11	1.51	6.05
47	0.23	0.07	15.36	1.44	7.71
48	0.35	0.05	18.20	0.84	10.61
49	0.28	0.04	19.71	1.64	13.01
50	0.27	0.01	27.02	2.36	16.82
51	0.20	0.01	29.09	3.30	20.11
52	0.10	0.00	34.54	4.28	24.48
1	0.10	0.00	31.66	5.85	23.41
2	0.12	0.00	29.10	7.06	23.01
3	0.05	0.01	30.07	12.24	23.63
4	0.05	0.00	29.45	15.89	23.96
5	N/A	0.00	30.62	19.60	24.90
6	N/A	0.02	32.39	17.89	25.00
7	N/A	0.01	32.51	16.28	25.05
8	N/A	0.00	32.87	17.45	25.14
9	N/A	0.00	34.28	16.80	24.59
10	N/A	0.00	35.99	16.05	23.22
11	N/A	0.01	31.41	16.19	21.41
12	N/A	0.00	30.03	15.03	20.10
13	N/A	0.00	28.25	14.50	19.56
14	N/A	0.00	23.16	12.66	17.86
15	N/A	0.01	20.73	11.95	16.27
16	N/A	0.00	18.52	11.64	14.48
17	N/A	0.00	17.30	9.76	12.83
18	N/A	0.00	13.02	7.88	10.26
19	N/A	0.00	11.95	4.96	8.98
20	N/A	0.01	9.13	3.19	7.22
21	N/A	0.01	7.45	2.97	5.60
22	N/A	0.00	4.96	2.19	3.86
23	N/A	0.00	4.39	0.87	2.86
24	N/A	0.02	4.36	0.81	2.25
25	N/A	0.00	3.95	0.63	1.88
26	N/A	0.00	3.08	0.69	1.81
27	N/A	0.00	2.83	0.42	1.48
28	N/A	0.00	1.84	0.41	0.91
29	N/A	0.00	1.55	0.47	1.09
30	N/A	0.04	1.46	0.46	0.90
31	N/A	0.00	1.93	0.58	1.11
32	N/A	0.00	1.19	0.52	0.92
33	N/A	0.00	1.69	0.40	0.85
34	N/A	0.02	1.57	0.42	0.92

Figure 4 - Text description

a) Proportion of influenza A and B by age-group

Age Group	Proportion of Influenza A	Proportion of Influenza B	Total Number Influenza Detections
0 to 4	71.3%	28.7%	108
5 to 19	80.5%	19.5%	77
20 to 44	79.6%	20.4%	137
45 to 64	73.0%	27.0%	37
65+	75.0%	25.0%	32

b) Proportion of subtyped influenza A(H1N1) and A(H3N2) by age-group

Age Group	Proportion of A(H1N1)	Proportion of A(H3N2)	Total Number of Subtyped Influenza Detections
0 to 4	26.7%	73.3%	15
5 to 19	7.7%	92.3%	13
20 to 44	2.9%	97.1%	34
45 to 64	0.0%	100.0%	8
65+	0.0%	100.0%	8

Syndromic / Influenza-like Illness Surveillance

Healthcare Practitioners Sentinel Surveillance

In week 04, 0.9% of visits to healthcare professionals were due to influenza-like illness (ILI). The percentage of visits for ILI has decreased over the past few weeks after peaking in early January.

Since the beginning of the surveillance season, the percentage of visits for ILI has been within or near expected pre-pandemic levels (Figure 5). ILI symptoms are not specific to any one respiratory pathogen and can be due to influenza, or other respiratory viruses, including respiratory syncytial virus and even SARS-CoV-2, the virus that causes COVID-19.

This indicator should be interpreted with caution as there have been changes in healthcare seeking behavior of individuals and a smaller number of sentinels reporting compared to previous seasons.

Number of Sentinels Reporting in Week 04: 45

The shaded area represents the maximum and minimum percentage of percentage of participants reporting cough and fever by week, from seasons 2014-2015 to 2019-2020. Data from week 11 of the 2019-2020 season onwards are excluded from the historical comparison due to the COVID-19 pandemic.

Figure 5 - Text description

Surveillance Week	2021-2022	2020-2021	Average	Min	Max
35	0.6%	0.1%	0.6%	0.4%	0.9%
36	1.2%	0.2%	0.6%	0.4%	0.9%
37	0.6%	0.4%	0.7%	0.5%	1.0%
38	0.9%	0.3%	0.7%	0.6%	1.0%
39	1.0%	0.4%	0.9%	0.5%	1.2%
40	0.5%	0.2%	1.2%	0.8%	1.7%
41	1.1%	0.4%	1.7%	0.8%	2.8%
42	1.2%	0.5%	1.6%	1.2%	2.1%
43	0.9%	0.3%	1.2%	0.8%	1.7%
44	0.6%	0.3%	1.2%	0.7%	1.7%
45	1.0%	0.4%	1.2%	0.9%	1.5%
46	0.9%	0.8%	1.4%	1.2%	1.8%
47	0.7%	0.3%	1.6%	1.1%	2.2%
48	1.1%	0.5%	1.5%	1.1%	2.2%
49	0.9%	0.5%	1.7%	1.0%	2.8%
50	1.1%	0.4%	1.5%	1.1%	1.7%
51	1.7%	0.5%	1.9%	1.4%	2.7%
52	1.5%	0.5%	2.0%	1.0%	3.1%
1	2.1%	0.7%	3.4%	1.9%	5.4%
2	1.6%	0.4%	3.4%	1.8%	5.7%
3	1.4%	0.2%	2.3%	1.3%	3.7%
4	0.9%	0.3%	2.0%	1.1%	2.9%
5	N/A	0.2%	2.1%	1.4%	3.1%
6	N/A	0.5%	2.4%	1.4%	4.0%
7	N/A	0.3%	2.4%	0.9%	3.5%
8	N/A	0.2%	2.3%	0.8%	3.4%
9	N/A	0.2%	2.3%	0.9%	3.1%
10	N/A	0.2%	2.0%	1.0%	2.8%
11	N/A	0.2%	1.9%	1.1%	2.8%
12	N/A	0.3%	1.6%	0.6%	2.6%
13	N/A	0.4%	1.6%	1.1%	2.6%
14	N/A	0.2%	1.7%	1.1%	3.0%
15	N/A	0.3%	1.3%	0.9%	1.9%
16	N/A	0.3%	1.2%	0.8%	1.7%
17	N/A	0.4%	1.2%	0.7%	1.7%
18	N/A	0.5%	1.3%	0.5%	2.0%
19	N/A	0.3%	0.9%	0.6%	1.3%
20	N/A	0.5%	1.1%	0.6%	1.5%
21	N/A	0.3%	0.9%	0.5%	1.3%
22	N/A	0.3%	0.7%	0.3%	1.0%
23	N/A	0.2%	0.8%	0.6%	1.0%
24	N/A	0.2%	0.7%	0.6%	1.0%
25	N/A	0.2%	0.6%	0.4%	0.8%
26	N/A	0.2%	0.8%	0.5%	1.4%
27	N/A	0.3%	0.6%	0.5%	0.7%
28	N/A	0.1%	0.7%	0.5%	1.3%
29	N/A	0.3%	0.9%	0.6%	1.7%
30	N/A	0.2%	0.6%	0.2%	0.9%
31	N/A	0.2%	0.4%	0.2%	0.6%
32	N/A	0.2%	0.8%	0.3%	1.2%
33	N/A	0.3%	0.7%	0.4%	1.3%
34	N/A	0.5%	0.7%	0.4%	1.5%

FluWatchers

In week 04, 12,585 participants reported to FluWatchers, of which 0.56% reported symptoms of cough and fever (Figure 6). The percentage of participants reporting cough and fever peaked in late December and has decreased to levels seen in the fall.

The reports of cough and fever are not specific to any one respiratory pathogen and can be due to influenza, or other respiratory viruses, including respiratory syncytial virus, rhinovirus, and even SARS-CoV-2, the virus that causes COVID-19. FluWatchers reporting is not impacted by changes in health services or health seeking behaviours.

Among the 69 participants who reported cough and fever:

• 71% consulted a healthcare professional;
• 87% reported days missed from work or school, resulting in a combined total of 259 missed days of work or school (average of 4.3 days).

The Northwest Territories had the highest participation rate this week (57 participants per 100,000 population) and the neighbourhood of K0A had the highest number of participants (154) See what is happening in your Open Maps.

If you are interested in becoming a FluWatcher, sign up today.

Number of Participants Reporting in Week 04: 12,585

The shaded area represents the maximum and minimum percentage of percentage of participants reporting cough and fever by week, from seasons 2014-2015 to 2019-2020. Data from week 11 of the 2019-2020 season onwards are excluded from the historical comparison due to the COVID-19 pandemic.

Figure 6 - Text description

Surveillance Week	2021-2022	2020-2021	Average	Min	Max
35	0.23%	0.22%	N/A	N/A	N/A
36	0.28%	0.21%	N/A	N/A	N/A
37	0.49%	0.38%	N/A	N/A	N/A
38	0.54%	0.29%	N/A	N/A	N/A
39	0.54%	0.45%	N/A	N/A	N/A
40	0.58%	0.49%	2.51%	2.18%	2.71%
41	0.46%	0.44%	2.18%	1.81%	2.57%
42	0.38%	0.33%	1.80%	1.61%	2.03%
43	0.53%	0.17%	1.87%	1.49%	2.18%
44	0.51%	0.26%	1.57%	1.39%	1.78%
45	0.54%	0.29%	1.83%	1.42%	2.32%
46	0.41%	0.28%	1.83%	1.22%	2.15%
47	0.57%	0.31%	1.93%	1.44%	2.39%
48	0.51%	0.26%	2.43%	1.67%	3.35%
49	0.40%	0.17%	2.56%	1.97%	3.16%
50	0.60%	0.15%	2.91%	2.12%	3.79%
51	1.03%	0.22%	3.18%	2.53%	3.95%
52	1.51%	0.10%	3.98%	2.81%	5.38%
1	1.08%	0.12%	3.84%	2.85%	4.76%
2	0.99%	0.21%	2.94%	1.90%	3.93%
3	0.77%	0.12%	3.25%	2.35%	4.84%
4	0.56%	0.12%	3.12%	2.13%	4.23%
5	0.00%	0.17%	3.19%	2.62%	3.59%
6	0.00%	0.11%	3.47%	2.76%	4.28%
7	0.00%	0.16%	3.18%	2.58%	3.79%
8	0.00%	0.06%	3.09%	2.54%	3.65%
9	0.00%	0.10%	2.81%	2.38%	3.53%
10	0.00%	0.18%	2.58%	2.12%	3.11%
11	0.00%	0.16%	2.33%	1.89%	2.63%
12	0.00%	0.17%	2.60%	2.46%	2.82%
13	0.00%	0.17%	2.48%	1.99%	3.06%
14	0.00%	0.19%	2.13%	1.35%	2.58%
15	0.00%	0.21%	1.78%	1.60%	1.93%
16	0.00%	0.14%	2.00%	1.47%	2.44%
17	0.00%	0.22%	1.73%	1.40%	2.31%
18	0.00%	0.15%	1.50%	1.19%	2.09%
19	0.00%	0.14%	N/A	N/A	N/A
20	0.00%	0.15%	N/A	N/A	N/A
21	0.00%	0.09%	N/A	N/A	N/A
22	0.00%	0.10%	N/A	N/A	N/A
23	0.00%	0.08%	N/A	N/A	N/A
24	0.00%	0.13%	N/A	N/A	N/A
25	0.00%	0.12%	N/A	N/A	N/A
26	0.00%	0.16%	N/A	N/A	N/A
27	0.00%	0.11%	N/A	N/A	N/A
28	0.00%	0.20%	N/A	N/A	N/A
29	0.00%	0.20%	N/A	N/A	N/A
30	0.00%	0.22%	N/A	N/A	N/A
31	0.00%	0.21%	N/A	N/A	N/A
32	0.00%	0.25%	N/A	N/A	N/A
33	0.00%	0.31%	N/A	N/A	N/A
34	0.00%	0.50%	N/A	N/A	N/A

Influenza Outbreak Surveillance

In week 04, one ILI outbreak in a school/daycare was reported.

To date this season (August 29, 2021 to January 29, 2022), 16 ILI outbreaks and no laboratory-confirmed influenza outbreaks have been reported. All ILI outbreaks have been reported in schools and/or daycares. The most recent laboratory-confirmed influenza outbreak occurred in week 24 (week ending June 13, 2020) of the 2019-2020 season.

Outbreaks of ILI are not specific to any one respiratory pathogen and can be due influenza, or other respiratory viruses, including respiratory syncytial virus, rhinovirus, and even COVID-19. Many respiratory viruses in addition to the flu commonly circulate during the fall and winter, and can cause clusters of cases with respiratory illness which could be captured as ILI. For more information on the respiratory viruses currently circulating in Canada, please refer to the Respiratory Virus Detections in Canada.

Number of provinces and territories^{Footnote 1} reporting in week 04: 13 out of 13

Influenza Severe Outcomes Surveillance

Provincial/Territorial Influenza Hospitalizations and Deaths

In week 04, no influenza-associated hospitalizations were reported by participating provinces and territories^{Footnote 2}.

To date this season (August 29, 2021 to January 29, 2022), less than five influenza-associated hospitalizations were reported by participating provinces and territories with the most recent influenza-associated hospitalization reported in week 52 (week ending January 1, 2022).

Number of provinces and territories reporting in week 04: 13 out of 13

Pediatric Influenza Hospitalizations and Deaths

In week 04, no influenza-associated pediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network.

To date this season (August 29, 2021 to January 29, 2022), seven pediatric influenza-associated hospitalizations and less than five intensive care unit (ICU) admissions were reported by the IMPACT network.

Adult Influenza Hospitalizations and Deaths

In week 04, no influenza-associated adult (≥16 years of age) hospitalizations were reported by the Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) network.

To date this season (August 29, 2021 to January 22, 2022), less than five influenza-associated adult (≥16 years of age) hospitalizations have been reported by the CIRN SOS network.

Influenza Strain Characterization

To date this season (August 29, 2021 to January 29, 2022), less than five influenza-associated adult (≥16 years of age) hospitalizations have been reported by the CIRN SOS network.

Influenza A(H3N2)

Genetic Characterization

Among the 17 influenza A(H3N2) viruses genetically characterized, sequence analysis of the HA gene of these viruses showed that they all belonged to genetic group 3C.2a1b.2a2.

A/Cambodia/e0826360/2020 (H3N2)-like virus is the influenza A(H3N2) component of the 2021-2022 Northern Hemisphere seasonal influenza vaccine and belongs to genetic group 3C.2a1b.2a1.

A/Darwin/6/2021 (H3N2)-like virus is the influenza A(H3N2) component of the 2022 Southern Hemisphere seasonal influenza vaccine and belongs to the genetic group 3C.2a1b.2a2.

Antigenic Characterization

Among the 17 A(H3N2) viruses characterized:

• 4 viruses were antigenically similar to A/Cambodia/e0826360/2020 (H3N2)-like virus
• 13 showed reduced titers with antisera raised against egg-grown A/Cambodia/e0826360/2020 (H3N2)-like virus.

Influenza A(H1N1)

Antigenic Characterization

Among the two A(H1N1) viruses characterized:

• One H1N1 virus characterized was antigenically similar to A/Wisconsin/588/2019.
• One H1N1 showed reduced titer with ferret antisera raised against cell culture-propagated A/Wisconsin/588/2019

A/Wisconsin/588/2019 is the influenza A(H1N1) component of the 2021-2022 Northern Hemisphere seasonal influenza vaccine.

Antiviral Resistance

The NML also tests influenza viruses received from Canadian laboratories for antiviral resistance.

Oseltamivir

19 influenza viruses (17 A(H3N2) and 2 A(H1N1)) were tested for resistance to oseltamivir:

• All influenza viruses were sensitive to oseltamivir.

Zanamivir

19 influenza viruses (17 A(H3N2) and 2 A(H1N1)) were tested for resistance to zanamivir:

• All influenza viruses were sensitive to zanamivir.

Influenza Vaccine Monitoring

Vaccine monitoring refers to activities related to the monitoring of influenza vaccine coverage and effectiveness.

Vaccine Coverage

Influenza vaccine coverage estimates for the 2021-2022 season are anticipated to be available in February or March 2022.

Vaccine Effectiveness

Influenza vaccine effectiveness estimates for the 2021-2022 season are anticipated to be available in February or March 2022, pending the resumption of community transmission of seasonal influenza.

Provincial and International Surveillance Links

See Influenza surveillance resources

Notes

The data in the FluWatch report represent surveillance data available at the time of writing. All data are preliminary and may change as updates are received.

To learn more about the FluWatch program, see the Overview of influenza monitoring in Canada page.

For more information on the flu, see our Flu (influenza) web page.

We would like to thank all the FluWatch surveillance partners participating in this year's influenza surveillance program.

This report is available on the Government of Canada Influenza webpage.

Ce rapport est disponible dans les deux langues officielles.