Progress Toward Regional Measles Elimination — Worldwide, 2000–2021

Anna A. Minta, MD; Matt Ferrari, PhD; Sebastien Antoni, MPH; Allison Portnoy, ScD; Alyssa Sbarra, MPH; Brian Lambert; Sarah Hauryski; Cynthia Hatcher, MPH; Yoann Nedelec, MPH; Deblina Datta, MD; Lee Lee Ho, MPH; Claudia Steulet, MPH; Marta Gacic-Dobo, MSc; Paul A. Rota, PhD; Mick N. Mulders, PhD; Anindya S. Bose, MD; William A. Perea; Patrick O'Connor, MD

Disclosures

Morbidity and Mortality Weekly Report. 2022;71(47):1489-1495.

Surveillance Performance and Reported Measles Incidence

WHO's Global Measles and Rubella Laboratory Network (GMRLN) supports countries in providing standardized quality-controlled laboratory testing for measles and rubella. Among the 135 (70%) countries that reported discarded cases, 47 (35%) achieved the sensitivity indicator target of two or more discarded cases per 100,000 population in 2021, compared with 45 (31%) of 143 countries reporting in 2020. In 2021, GMRLN laboratories received 122,735 specimens for measles testing compared with 122,116 specimens in 2020.

Countries report the number of incident measles cases to WHO and UNICEF annually, using the Joint Reporting Form.^¶¶ During 2000–2016, the number of reported measles cases decreased by 84%, from 853,479 to 132,490. Reported measles cases peaked at 873,022 in 2019, then declined to 159,073 in 2020, and 123,981 in 2021. From 2000 to 2016, annual measles incidence decreased 88%, from 145 cases per 1 million population to 18; measles incidence then increased to 120 cases per million in 2019 and decreased 82% to 21 in 2020 and 22% to 17 in 2021. In 2021, 22 countries in two WHO regions were affected by large and disruptive outbreaks***; 18 (82%) outbreaks occurred in countries in the African Region and four (18%) in the Eastern Mediterranean Region (Supplementary Table, https://stacks.cdc.gov/view/cdc/122049).

Genotypes detected from measles cases^††† were reported by 27 (33%) of the 82 countries reporting at least one measles case in 2021, compared with 45 (39%) of 115 countries reporting at least one measles case in 2020. The number of genotypes detected decreased from 13 in 2002 to six in 2014, three in 2020, and two in 2021. A total of 1,615 sequences were reported in 2020; among 648 reported sequences in 2021, 221 (34%) were D8 and 426 (66%) were B3.

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Abstract and Introduction
Immunization Activities
Surveillance Performance and Reported Measles Incidence
Measles Case and Mortality Estimates
Regional Verification of Measles Elimination
Discussion
References
Sidebar

^¶¶Only countries that reported data are in the numerator and denominator. Countries do not provide WHO with their reasons for not reporting measles cases. https://immunizationdata.who.int/pages/incidence/measles.html (Accessed September 20, 2022).
***The IA2030 global monitoring framework defines large and disruptive outbreaks as having at least 20 cases per 1 million population.
^†††Data as of September 20, 2022. https://who-gmrln.org/means2

Table 1. Estimates of regional immunization coverage with the first and second doses of measles-containing vaccine administered through routine immunization services, reported measles cases, and measles incidence, by World Health Organization region — worldwide, 2000–2021
Yr/WHO region (no. of countries in region)	Percentage				No. of reported measles cases^§ (% of total cases)	Measles incidence^§,¶,**
Yr/WHO region (no. of countries in region)	MCV1* coverage	Countries with ≥90% MCV1 coverage^†	MCV2* coverage	Reporting countries with <5 measles cases per 1 million population^§,¶	No. of reported measles cases^§ (% of total cases)	Measles incidence^§,¶,**
Total (all regions)
2000 (191)	72	44	17	33	853,479 (100)	145
2010 (193)	84	63	42	59	343,806 (100)	50
2016 (194)	85	61	67	64	132,490 (100)	18
2019 (194)	86	62	71	44	873,022 (100)	120
2020 (194)	83	51	72	57	159,073 (100)	21
2021 (194)	81	47	71	66	123,981 (100)	17
African
2000 (46)	53	9	5	6	520,102 (60.9)	832
2010 (46)	72	36	5	30	199,174 (57.9)	232
2016 (47)	68	34	22	49	36,269 (27.4)	37
2019 (47)	70	30	33	34	618,595 (70.9)	560
2020 (47)	69	19	40	30	115,369 (72.5)	106
2021 (47)	68	23	41	34	89,602 (72.3)	83
Americas
2000 (35)	93	63	65	89	1,754 (0.2)	2
2010 (35)	93	74	67	100	247 (0.1)	0.3
2016 (35)	92	66	80	97	97 (0.1)	0.1
2019 (35)	87	69	72	89	21,971 (2.5)	32
2020 (35)	85	43	72	97	9,996 (6.3)	10
2021 (35)	84	31	75	97	682 (0.6)	0.7
Eastern Mediterranean
2000 (21)	71	57	27	14	38,592 (4.5)	87
2010 (21)	76	62	52	38	10,072 (2.9)	17
2016 (21)	82	57	73	52	6,275 (4.7)	10
2019 (21)	83	52	76	38	18,458 (2.1)	26
2020 (21)	83	48	77	48	6,769 (4.3)	10
2021 (21)	82	48	77	52	26,089 (21.0)	40
European
2000 (52)	91	60	48	38	37,421 (4.4)	50
2010 (53)	94	83	80	68	30,625 (8.9)	34
2016 (53)	93	81	88	77	4,440 (3.4)	5
2019 (53)	96	85	92	30	106,130 (12.2)	117
2020 (53)	94	77	91	70	10,945 (6.9)	14
2021 (53)	94	70	91	91	99 (0.1)	0.1
South-East Asia
2000 (10)	62	27	3	0	78,558 (9.2)	51
2010 (11)	83	45	15	36	54,228 (15.8)	30
2016 (11)	89	64	75	27	27,530 (20.8)	14
2019 (11)	94	73	83	27	29,389 (3.4)	15
2020 (11)	88	64	80	45	9,389 (5.9)	5
2021 (11)	86	55	78	55	6,448 (5.2)	3
Western Pacific
2000 (27)	85	48	2	26	177,052 (20.7)	106
2010 (27)	97	63	87	63	49,460 (14.4)	28
2016 (27)	96	63	93	48	57,879 (43.7)	31
2019 (27)	95	70	93	41	78,479 (9.0)	41
2020 (27)	94	63	94	37	6,605 (4.2)	4
2021 (27)	91	59	91	48	1,061 (0.9)	0.6

Abbreviations: MCV1 = first dose of measles-containing vaccine; MCV2 = second dose of measles-containing vaccine; WHO = World Health Organization.
*https://immunizationdata.who.int/pages/coverage/mcv.html (Accessed September 29, 2022).
^†Denominator is the number of WHO member states.
^§https://immunizationdata.who.int/pages/incidence/measles.html (Accessed September 29, 2022).
^¶Population data from United Nations Department of Economic and Social Affairs, Population Division, 2022. Any country not reporting measles cases for that year was removed from both the numerator and denominator in calculating incidence.
**Cases per 1 million population.

Table 2. Estimated number of measles cases and deaths,* by World Health Organization region — worldwide, 2000 and 2021
Yr/WHO region (no. of countries in region)	No. (95% CI)		Estimated reduction in measles mortality, %2000–2021	Cumulative no. of measles deaths averted by vaccination2000–2021
Yr/WHO region (no. of countries in region)	Estimated no. of measles cases	Estimated no. of measles deaths	Estimated reduction in measles mortality, %2000–2021
Total, all regions
2000 (191)	34,012,634 (27,393,416–42,901,683)	761,038 (561,895–993,312)	83	55,812,741
2021 (194)	9,484,464 (5,681,867–14,881,517)	127,656 (74,444–197,500)	83	55,812,741
African
2000 (46)	10,965,152 (7,134,948–14,649,839)	356,299 (227,304–488,539)	81	19,499,793
2021 (47)	4,430,595 (2,619,358–7,030,815)	66,229 (38,811–106,293)	81	19,499,793
Americas
2000 (35)	8,770 (4,385–35,080)	NA^†	61	4,343,128
2021 (35)	3,410 (1,705–13,640)	NA^†	61	4,343,128
Eastern Mediterranean
2000 (21)	4,370,190 (3,295,576–6,213,952)	150,299 (115,962–205,857)	67	9,553,930
2021 (21)	2,303,170 (1,304,581–3,075,854)	48,979 (26,638–72,045)	67	9,553,930
European
2000 (52)	911,710 (733,732–1,353,344)	3,869 (3,098–4,747)	97	1,146,475
2021 (53)	86,196 (25,252–208,956)	132 (34–352)	97	1,146,475
South-East Asia
2000 (10)	12,395,953 (11,108,235–14,268,354)	224,822 (192,623–266,165)	95	16,546,297
2021 (11)	1,702,699 (1,399,591–2,321,389)	10,230 (8,328–13,538)	95	16,546,297
Western Pacific
2000 (27)	5,360,859 (5,116,541–6,381,114)	25,746 (22,907–27,993)	92	4,723,119
2021 (27)	958,395 (331381–2,230,863)	2,085 (633–5,267)	92	4,723,119

Abbreviations: NA = not applicable; WHO = World Health Organization.
*The measles mortality model used to generate estimated measles cases and deaths is rerun each year using the new and revised annual WHO-UNICEF estimates of national immunization coverage data as well as updated surveillance data. In 2021, data on case fatality from an updated systematic review and a suite of covariates with known relationships to case fatality were used in a Bayesian meta-regression modeling framework to produce estimates of measles case fatality ratios; therefore, the estimated number of cases and mortality estimates for 2000–2020 in this report differs from previous reports.
^†Estimated measles mortality was too low to allow reliable measurement of mortality reduction.