Influenza in temperate and tropical Asia: a review of epidemiology and vaccinology

Figures & data

Table 1. Summary of influenza data by continent reported to FluNet, 2017–2018. Continent definition per WHO influenza transmission zones. Population data from the United Nations Population Division (2019).

	Africa	Asia	Europe	Latin America	North America	Oceania	Global
No of countries reporting data	30	43	40	39	3	5	160
No of WHO transmission zones	5	5	3	3	1	1	18
Population in countries reporting data, ‘000s (2018)	1 087 244	4 468 571	745 894	638 645	364 234	39 411	7 344 000
Population of region, ‘000s (2018)	1 275 921	4 560 667	746 419	642 217	364 296	41 571	7 631 091
FluNet coverage (% of population)	85.2%	98.0%	99.9%	99.4%	100.0%	94.8%	96.2%
Number of influenza cases per year reported to FluNet	7 811	136 759	184 780	28 861	294 283	8 462	660 954
Number people per reported influenza case	139 203	32 675	4 037	22 128	1 238	4 657	11 111
Number influenza cases reported per 100,000 people	0.7	3.1	24.8	4.5	80.8	21.5	9.0

Figure 1. (a) Map of the 27 countries with weekly influenza data available from 2011 to 2018 on FluNet. Color groupings by WHO transmission zone [South-East (orange), Southern (yellow), Eastern (light blue), Central (dark blue), Western (green)]. (b) Number of influenza cases reported per week from 2011 to 2018 [Note for 1B and 1C labels indicate the beginning of the respective year]. (c) Heat map of weekly influenza cases (A/H1, A/H3 and B combined) reported to FluNet from 2011 to 2018 normalized to proportion per year (where 1 = week with highest proportion). Countries organized by WHO transmission zone and by the latitude of most populous city in that country from North to South. (d) Time-series analysis to infer the month of primary seasonal influenza peak from FluNet surveillance data, stratified by the latitude of countries most populous city and grouped by WHO influenza transmission zone [4-weekly smoothed and detrended by proportion of cases per year].

Table 2. Summary of HI persistence data following high-dose or MF59 adjuvanted influenza vaccination compared with the standard-dose vaccine in adults aged ≥65years. NS = not significant, *p ≤ 0.05.

			Day 21–42 (Seroconversion)		Day 180		Day 360
No	Study	Type	IIV3	Comparator	IIV3	Comparator	IIV3	Comparator
High dose influenza vaccine (Fluzone HD)
1	Nace, 2011–12^Citation46	A/H1	27.4	78.2*	28.3	59.7	-	-
		A/H3	10.2	26.2*	9.4	22.3*	-	-
		B	14.3	25.6*	15.4	22.9	-	-
2^a	Nace, 2012-13^Citation46	A/H1	50	45.6	51.8	46.8	-	-
		A/H3	14.2	23.4*	13.4	24.7*	-	-
		B	17.4	26.0*	18.9	25.3	-	-
3^b	Kim^Citation47	A/H1	35	71*	-	-	22	28
		A/H3	29	81*	-	-	18	24
		B	41	80*	-	-	27	34
4^b	Merani^Citation48	A/H1	61	97*	50	54	-	-
		A/H3	91	141*	67	83	-	-
		B	102	107	84	63	-	-
Adjuvanted influenza vaccine (Fluad)
5	Minutello^Citation49	A/H1	31	45	-	-	14	20
		A/H3	149	189	-	-	55	57
		B	74	115*	-	-	33	38
6^c	Gasparini^Citation50	A/H1	167	191	NS		-	-
		A/H3	55	103*	NS		-	-
		B	70	102*	NS		-	-
7	Song^Citation29	A/H1	81.2	78.8	35.6	40.7	-	-
		A/H3	92.4	157.7*	28.8	48.4	-	-
		B	24.1	34.5	11.0	16.0	-	-
8	Seo^Citation51	A/H1	68.1	92.7	25.4	32.5	-	-
		A/H3	54.7	102.3*	48.3	63.2	-	-
		B	12.2	16.5	10.7	12.0	-	-
9^d	Frey^Citation42	A/H1	141	198*	68	71	52	49
		A/H3	337	544*	91	123*	54	70*
		B	48	55*	22	25	20	21
10^e	Schiefele^Citation52	A/H1	79.7	113.4*	39.0	47.4	-	-
		A/H3	70.1	101.4*	37.6	44.3	-	-
		B	221.2	239.8	158.0	158.7	-	-

^aDifferent subjects included each year;

^bGMT estimated from graph;

^cGMT not provided;

^dGMT data from day 180–360 from a persistence cohort (~6% subset);

^eData at day 180 from personal communication with authors.

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