Measles Elimination, 2000–2017: 21.1 Million Deaths Prevented, and a Resurgence

In 2010, the World Health Assembly set three measles milestones for 2015:

1. first-dose vaccine (MCV1) coverage of 90% or more nationally, and 80% or more in every district;
2. global incidence below 5 cases per million people;
3. measles deaths down 95% from 2000.

In 2012, its Global Vaccine Action Plan aimed to eliminate measles in four of the six World Health Organization (WHO) regions by 2015 and five by 2020, and countries in all six regions have adopted 2020 elimination goals. This report, by WHO and CDC authors, tracks progress through 2017.

Headline numbers, 2000 → 2017

Over the period, measles vaccination prevented an estimated 21.1 million deaths — 19.3 million of them in the 73 countries supported by Gavi, the Vaccine Alliance, and most in the African Region.

Vaccination

First dose. Global MCV1 coverage has been stuck at 84–85% since 2010, with wide regional gaps:

• 118 countries (61%) reached at least 90% MCV1 in 2017 — up from 85 (44%) in 2000, but down slightly from 120 in 2016. The biggest gains in that share came in Africa (9% → 34%) and South-East Asia (27% → 64%).
• Only 45 countries (23%) reached 80% in every district.
• An estimated 20.8 million infants missed their first dose in 2017, most of all in Nigeria (3.9 million), India (2.9 million), Pakistan and Indonesia (1.2 million each), Ethiopia (1.1 million) and Angola (0.7 million).

Second dose. MCV2 coverage rose fastest in South-East Asia (3% → 77%) and the Western Pacific (2% → 94%). Laos, Namibia and Nicaragua introduced it in 2017.

Mass campaigns. In 2017, about 205 million people got an extra dose in 53 supplementary immunization activities across 39 countries; only 26 (49%) reached 95% coverage. From 2010 to 2017, 1,476,826,523 people were vaccinated in 443 campaigns.

Surveillance

• 189 countries (97%) ran case-based surveillance in at least part of their territory, and 191 (98%) had access to WHO's Global Measles and Rubella Laboratory Network.
• But surveillance was often weak: only 73 of 152 reporting countries (48%) met the sensitivity target of at least two discarded measles and rubella cases per 100,000.
• Reported cases rose 31% from 2016 to 2017 — partly because more countries reported (184 vs 176 of 194). They doubled in Africa, rose 6,358% in the Americas, 481% in the Eastern Mediterranean, 458% in Europe and 3% in South-East Asia, but fell 82% in the Western Pacific.
• Genotypes: only five of the 24 known measles genotypes were detected in 2016 and 2017, down from 11 in 2005–2008. Of 5,789 sequences in 2017, B3 (45.6%) and D8 (43.9%) dominated, followed by H1 (9.4%), D9 and D4.

Elimination status in 2017

• All six regions now have verification commissions, after Africa and the Eastern Mediterranean set theirs up in 2017.
• Americas: declared free of endemic measles in September 2016 — but by July 2018, endemic transmission had returned in Venezuela, spilling into neighboring countries; the other 34 countries in the region kept their status.
• Europe: elimination verified in 37 countries (70%); endemic transmission re-established in the Russian Federation and Germany, and likely in others amid a resurgence.
• South-East Asia: Maldives and Bhutan verified.
• Western Pacific: Australia, Brunei, Cambodia, Japan, New Zealand and South Korea, plus Hong Kong and Macao (China), verified. Measles incidence there hit an all-time low.
• Africa and the Eastern Mediterranean: no countries verified.

The area between the two lines is the deaths prevented by vaccination. Image from the Centers for Disease Control and Prevention

Why progress stalled

The 2015 milestones were missed: first-dose coverage has stagnated for nearly a decade, second-dose coverage is only 67%, many campaigns fell short of 95%, and since 2016 incidence has risen globally and in five of six regions. The Venezuelan and European outbreaks show how fragile the gains are.

Limitations: campaign coverage can be distorted by miscounted doses, doses given outside the target age and poor population estimates; big gaps between estimated and reported incidence show surveillance varies widely; and the mortality model inherits the biases of its inputs.

What is needed

• Raise MCV1 and MCV2 coverage, and run high-quality campaigns that reach unvaccinated and under-vaccinated children.
• Strengthen case-based surveillance to catch outbreaks early, and investigate them thoroughly to learn why children are being missed.
• Update monitoring: WHO's Strategic Advisory Group of Experts on Immunization has approved new country classifications and changes to how elimination is verified.
• Link measles and rubella elimination with post-2020 immunization goals, and keep up political commitment and sustained investment.

Sources

Based on "Progress Toward Regional Measles Elimination — Worldwide, 2000–2017," by Alya Dabbagh, Rebecca L. Laws, Claudia Steulet, Laure Dumolard, Mick N. Mulders, Katrina Kretsinger, James P. Alexander, Paul A. Rota and James L. Goodson, Morbidity and Mortality Weekly Report 67(47), Centers for Disease Control and Prevention; a work of the United States government in the public domain.