By Amanda Rachel Brunetti
The measles outbreak that began in early October 2019 across the Pacific Island region is ongoing. A disease alert issued by Reliefweb and a situation report published by WHO/UNICEF provide recent updates on the countries affected by the outbreak. These updates have been summarized below.
Immunization against measles is an effective, well-established method for disease prevention. The herd immunity threshold for measles is 95%, meaning that at least 95% of the population must be vaccinated in order to prevent [further] transmission of the virus. In response to the current outbreak, the Ministries of Health (MoH) of many Pacific countries have implemented strategies to strengthen their health systems, in large part by instituting mass vaccination campaigns. Though public health strategies have successfully reduced the scale of the outbreak, WHO reports the risk of importation of cases across the islands as moderate and recommends close monitoring of inter- and intra-island movement.
American Samoa (Population 51,000)
No new confirmed cases have been reported since mid-December 2019.
An initial public health emergency was declared in response to the measles outbreak in American Samoa mid-November 2019, which was extended on December 8 to last until early February 2020. Immediately following the [secondary] outbreak declaration, a mass vaccination campaign for adults aged 19 years and older was enforced; by December 30 12,152 doses were administered.
According to a report published on December 30 by the American Samoa Department of Health, approximately 98% of American Samoan children (12 months-18 years) have received the first dose of MMR and 90% of these children have received the second.
Fiji (Population 930,000)
All 28 cases of measles, including two new cases, have been confined to the Central Division, where circulation is ongoing but the number of new cases per week has decreased. The most recent confirmed case was a 10 month-old baby who is currently in isolation in their home.
An article by the Fijian Broadcasting Corporation reports that the Fiji MoH and National Measles Taskforce have lifted the mass gathering advisory that had been instituted when the outbreak began in November. However, citizens are still advised to take precautions, in particular ensuring vaccination status. Since the outbreak was declared, approximately 459,000 people have been immunized against measles. Current national vaccine coverage is 95.3% in children aged 6 months to 5 years and is 91% in those aged 19 to 39 years.
Kiribati (Population 110,000)
One new laboratory-confirmed case has been reported since late December. Active case finding is being employed where suspected cases have been reported and investigation is ongoing.
A report from the Kiribati Ministry of Health and Medical Services records a 96% national vaccination coverage rate in those aged 12 months to 14 years as of July 2019, although gaps have been identified in routine immunization. The Measles Taskforce has been working since early November to close this gap by addressing the unvaccinated populations.
Notably, there is also currently an acute diarrhea and vomiting (ADV)/rotavirus outbreak in Kiribati.
Samoa (Population 201,000)
The rate of measles cases has declined rapidly since the peak of the outbreak in late November and the situation is stabilizing. Twenty-two new cases and two deaths have been reported since late December.
The country suffers from dangerously low immunization rates, which may be partially attributed to an MMR vaccine tragedy that occurred in July 2019. A previous WHO/UNICEF situation report notes that prior to the current outbreak, only 31% of Samoan people were vaccinated against measles. To address this problem, the MoH mandated on November 18 that all citizens be vaccinated with MMR. To date, at least 134,499 people have received the vaccine.
Tonga (Population 106,000)
Fewer cases are being reported per reporting period; twenty-four new cases have been reported since late December.
Supplemental vaccination campaigns, including a mass program targeting adolescents and young adults, were instituted on October 10. As of the most recent reporting date at least 27,754 people have been vaccinated with MMR.
