The Ministry of Health has confirmed 394 people have been confirmed or suspected to have contracted measles as at November 26 in Tonga.

A situation report [2] issued on November 27 stated 344 (87%) of cases had occurred on the main island of Tongatapu, where the outbreak began. 

A smaller outbreak on Vava’u had a total of 44 (11%) cases. Additionally, 5 cases of rash illness had occurred in children on the island of ‘Eua, while a single case of rash illness had occurred in a child on the island of Ha’apai. 

Details of the case on Ha’apai were not yet available and data for this case was included in the analysis. 

Eight admissions to hospital had occurred among measles cases in this outbreak, with no deaths with the majority of cases managed in home isolation.

Transmission through boarding schools had been consistent with most cases among males, while female case numbers had increased as the outbreak progressed.

A total of 49 cases had occurred in children aged less than 5 years, an increase in the 34 cases for this age group in the previous report. 

Cases among adolescents and young people continued to form the majority of cases in this outbreak, with 325 (82%) cases occurring in people aged 10 to 24 years. In this age group, males were affected the most where 249 of 282 cases (88%) had occurred.

Consistent with previous reports, the predominant symptom report was rash in 387 out of 394 cases (98%) and fever in 340 out of 396 (86%). 

Of the 380 notified cases, 145 had documented vaccination histories, with the remaining 235 cases awaiting verification. Of the 145 cases with documentation, 119 (82%) had been fully vaccinated with at least 2 doses of measles-containing vaccine (MCV), while 26 (18%) had a single documented dose of MCV and 3 had no documented vaccination records. 

In addition, only 17 additional vaccination records had been accessed since the last report due to operational constraints and difficulty accessing paper records for these cases.

Vaccination

Vaccination efforts are targeting groups at greatest risk of measles infection, as well as those at greatest risk of severe illness, including infants aged 6 to 11 months, who are being offered a ‘zero dose’. Also included are extended family contacts of suspected and confirmed cases;
 and adolescents and young adults aged 10 to 24 years who have not been picked up in the school-based 
program and without documentation of two doses of MCV; and travellers.

The total number of vaccinations administered, as at November 22 was 11,869 which included school-based vaccinations of 8,432 and others of 3,437. Meanwhile clinics had completed vaccinations at all secondary schools on Tongatapu and started at schools on other islands. 

An increasing number of cases were occuring outside the predominant age group (10 to 19 years) and risk category group of children and infants.

The Tongan Ministry of Health wrote to UNICEF requesting 13,000 additional doses of MR vaccine. Some 7,000 doses of MR vaccine arrived in Tonga on 22 November. The remaining 6,000 vaccines are being sourced by UNICEF.

Excluding vaccines being held on other islands, the vaccine supply on the main island of Tongatapu is down to 1,400 doses remaining and vaccinations for overseas travellers are postponed until early next week, when the next consignment of vaccines is expected to arrive.