Epidemiology of measles

Measles is extremely contagious, but surviving the infection results in lifelong immunity,[1] so its continued circulation in a community depends on the generation of susceptible hosts by birth of children.

This concept was first recognized by Bartlett in 1957, who referred to the minimum number supporting measles as the critical community size (CCS).

Studies show that about 95% were immune by 15 years old, making it increasingly common for the incidence of measles to occur in young children.

Some examples of measles spreading between countries are: It has proven difficult to vaccinate a sufficient number of children in Europe to eradicate the disease, because of opposition on philosophical or religious grounds, or fears of side-effects, or because some minority groups are hard to reach, or simply because parents forget to have their children vaccinated.

[33] In January 2020, the World Health Organization announced that the death toll from the measles outbreak in the Democratic Republic of the Congo had reached 6,000, triple that of Ebola.

[42] In April 2022 cases were reported from the village of Makabvepi near the border with Mozambique, with child deaths from families that belonged to the Johane Marange Apostolic Church whose large Easter service and then a Passover celebration spread measles across the country.

The church publicly opposed vaccination and is closely aligned with President Emmerson Mnangagwa who attended the Passover gathering.

Vaccine hesitancy was amplified by churches discouraging immunization and urging members to rely on prayer and the intercession of pastors instead.

Immunization programs became widely spread during the 1970s, with an estimated 85% of the target population receiving one dose of vaccination by the end of the decade.

However, the frequent recurrence of significant outbreaks (including 6,178 cases in 1991 alone) showed Canada's 1-dose strategy was lacking, even with provinces requiring immunization for school attendance.

[49] The outbreak began on 8 January with unvaccinated individuals acquiring the disease whilst traveling to France, a country with high measles incidence, and returning home to Quebec.

[49] A measles outbreak was declared on 8 March 2014 in regions east of Vancouver in the Fraser Valley area where vaccination rates were known to be low in school and religious groups.

[54][55] Indigenous measles has been declared eliminated in North, Central, and South America; the last endemic case in the region was reported on November 12, 2002.

In June 2006, an outbreak in Boston resulted after a resident became infected in India,[57] and in October 2007, a Michigan girl who had been vaccinated contracted the disease overseas.

[63] Of the 64 cases, 54 were associated with importation of measles from other countries into the United States, and 63 of the 64 patients were unvaccinated or had unknown or undocumented vaccination status.

Around this time, Andrew Wakefield visited Minneapolis, teaming up with vaccine-skeptical groups to raise concerns about the MMR vaccine.

[96] As of 2020, the Pan America Health Organization reported that the measles outbreak is under control, and have increased vaccination rates in over 9 million children.

[101] In 2007, a large measles outbreak in Japan caused a number of universities and other institutions to close in an attempt to contain the disease.

[102][103] In early 2010, there was a serious outbreak of measles in the Philippines with 742 cases, leaving four unvaccinated children dead in the capital city of Manila.

[106] Despite the highest ever vaccination rate of 90% achieved in 2017 in the European region, number of measles cases tripled the next year reaching 82,596 with 72 of them resulting in death.

Some 90 infections of unvaccinated children were recorded by the Dutch National Institute for Public Health and the Environment (RIVM) by September 29.

It was expected the outbreak would spread to the region of the Veluwe, locally known as a bijbelgordel ("Bible Belt") with a large population of unvaccinated children on religious grounds.

This was caused by the preceding decade's low MMR vaccination rates, which created a population of susceptible children who could spread the disease.

[133] There have been growing concerns that the epidemic could spread to London and infect many more people due to poor MMR uptake,[134] prompting the Department of Health to set up a mass vaccination campaign targeted at one million school children throughout England.

[135] In April 2019 a senior epidemiologist at Public Health England said that confidence in the immunization program was high and that timing, availability and location of appointments were the main barriers to vaccination.

[137] 1,500 cases and three deaths were reported in the Irish outbreak of 2000, which occurred as a direct result of decreased vaccination rates following the MMR scare.

[143] Most recent reported cases of measles in Portugal are originally imported from other European countries (United Kingdom, France and Romania), Africa (Angola, South African and Ethiopia) and Asia (China).

[147] On December 5, 2023, the Romanian Ministry of Health announced in a press communique that there is a measles epidemic in Romania with over 2,000 cases registered.

[149] Fourteen cases have been reported in multiple Australian and New Zealand cities including Melbourne and Auckland in the period between December 7, 2013, and January 3, 2014.

[152] The outbreak was started with an unimmunised child becoming infected on a family trip to England, then developing measles back in Auckland.