Since 2022, Indonesia has recorded an increase in suspected and confirmed measles cases compared to previous years, according to a press release issued by the World Health Organization on 28 April 2023. Between 1 January and 3 April 2023, a total of 2161 suspected measles cases (848 laboratory-confirmed cases and 1313 clinically compatible suspected cases) have been reported across 18 of 38 provinces in Indonesia, primarily from the provinces of West Java (796 cases), Central Papua (770 cases), and Banten (197 cases).
Measles is endemic in Indonesia and is reported every year. However, in 2022 and 2023, there has been a significant increase in the number of confirmed cases, as compared to those reported annually since 2018: there were 920 reported cases in 2018, 639 in 2019, 310 in 2020, and 132 in 2021.
The current outbreak is characterized by suboptimal population immunity, including children without measles vaccination. Supplemental immunization activity was conducted in 2022, targeting children under 15 years old in high-risk provinces (Aceh, North Sumatra, Riau, Riau Islands, and West Sumatra), 9 – 59 months old in provinces in Java-Bali, and 9 months to 12 years old in the remaining provinces, with efforts to strengthen routine immunization and catch-up activities ongoing to address the population immunity gaps.
In 2022, a total of 4845 laboratory-confirmed Measles cases and six deaths (a case fatality ratio of 0.1%) were reported across 32 of the 38 provinces. The provinces mainly affected were Aceh (978 cases), West Sumatra (859 cases), Riau (500 cases), and East Java (459 cases). Annual trend analysis shows the number of cases reported annually in 2022 and currently in 2023 is higher than usual: there were 920 cases in 2018, 639 cases in 2019, 310 cases in 2020, and 132 cases in 2021.
In 2022, among the 4845 confirmed Measles cases with available age information, 93% (4502) were between 1 and 14 years old. However, a few cases have also been observed in the older age group, with at least 41 cases reported among people over 40. Among the confirmed cases, 67% had not received any dose of Measles-containing vaccine, 6% had received one dose, 7% had received both doses, and vaccination history was unknown for 21 % (991) of confirmed cases.
In 2023, among the 2076 confirmed cases with available age information, 95% (1978) were between 1 and 14 years of age. Of these confirmed cases, 75% had not received any dose of Measles-containing vaccine, while 11% had received one dose, 10% had received both doses, and vaccination history was unknown for 3%. Among these 2076 cases, 100% (212) of those younger than 9 months old, 87% (47) 9-12 months, and 66% (1303) of those aged 1-14 years had not received any dose of Measles-containing vaccine.
The current outbreak is mainly characterized by suboptimal population immunity, as evidenced by the increased gap in immunity. According to the World Health Organization/UNICEF Joint Reporting Form, the vaccination coverage in Indonesia in 2020 was 87% for Measles-containing-vaccine first-dose and only 65% for Measles-containing-vaccine second dose. In 2021, national coverage of Measles-containing-vaccine first-dose was 87%, and Measles-containing-vaccine second dose was 59%, with variation in administrative vaccination coverage at the sub-national level; these data indicate a very high number of children are susceptible to Measles infection.
Measles is a human disease caused by a Virus in the Paramyxovirus family. The Virus infects the respiratory tract, then spreads throughout the body. It can lead to major epidemics with significant morbidity and mortality, especially among vulnerable people. Among young and malnourished children, pregnant women, and immunocompromised individuals, including those with HIV, cancer or treated with immunosuppressives, Measles can cause serious complications, including severe diarrhea, blindness, encephalitis, pneumonia, and death.
Transmission is primarily person-to-person by airborne respiratory droplets that disperse rapidly when an infected person coughs or sneezes. Transmission can also occur through direct contact with infected secretions. Transmission from asymptomatic exposed immune persons has not been demonstrated. The Virus remains contagious in the air or on contaminated surfaces for up to two hours. A patient is infectious from four days before the start of the rash to four days after its appearance. There is no specific antiviral treatment for Measles, but most people recover within 2-3 weeks.
An effective and safe vaccine is available for prevention and control. The Measles-containing-vaccine first-dose is given at the age of nine months, while the Measles-containing-vaccine second dose is given at the age of 15 months. A 95% population coverage of Measles-containing-vaccine first-dose and Measles-containing-vaccine second dose is required to stop measles circulation.
In areas with low vaccination coverage, epidemics typically occur every two to three years and usually last between two and three months. However, their duration varies according to population size, crowding, and the population’s immunity status.
Several measles outbreaks have been reported in Indonesia between 2011 to 2023. One of the biggest outbreaks occurred in East Java province in 2016 where 3765 cases were reported, associated with low vaccination coverage levels.
Indonesia conducted supplemental immunization activity in 2022, targeting children under 15 years old for high-risk provinces (Aceh, North Sumatra, Riau, Riau Islands and West Sumatra), 9-59 months old for provinces in Java-Bali, and 9 months to 12 years old for the remaining provinces. Active case search and line listing of fever and rash cases is ongoing. Vitamin A is given to those identified with fever and rash during case investigation. Human resources have been deployed to the affected provinces to improve surveillance, particularly at the community level. Efforts are underway to procure reagents needed for laboratory testing enzyme-link immunosorbent assay. Promotion of routine immunization and catch-up activities is taking place via a multisectoral collaboration between the government, the community and partners, including the capacity building of immunization staff, strengthening the routine immunization information system and conducting a routine desk review to evaluate vaccination coverage. Coordination is taking place with the Indonesian Pediatric Society to disseminate the updated clinical management guidelines to health care workers. Capacity building on clinical management in the form of online training was conducted in 2022 in collaboration with the Indonesian Pediatric Society. Job aids have been developed to improve routine immunization coverage.
While Measles is endemic in Indonesia and is reported yearly, the magnitude and extent of this outbreak is high compared to previous years. Based on the current data and available information, the World Health Organization assess the overall risk of Measles at the national level as high for the following reasons: (1) Likely under-detection and under-reporting of Measles cases due to non-availability of laboratory reagents for confirmation of cases. The number of suspect measles cases reported in the Early Warning Alert and Response System has continued to increase since week 1 in 2023. An increase in hospitalization of suspect Measles cases is observed in some provinces, including Papua Province. (2) Low Measles-containing-vaccine coverage in most provinces, especially during the COVID-19 pandemic (2020-2021); 28% of the birth cohort in 2021 have not received any Measles vaccination and are thus at high risk for Measles infection. Also, 22% of the children have been only partially vaccinated. (3) Low Measles-containing vaccine supplemental immunization activities coverage in 2022, especially in high-risk provinces. There is vaccine hesitancy in the high-risk provinces, and limited capacity for outbreak response immunization, which is also impacted due to vaccine hesitancy. (4) Low surveillance sensitivity in 2020-2021. As surveillance improved in 2022, more cases were reported from the subnational level. The overall surveillance sensitivity of Measles and Rubella i.e., the non-Measles non-Rubella discard rate, was 3.33 per 100 000 population compared to the global standard of 2.0 or higher per 100 000 population. However, only 33% (170) districts achieved at least 2 non-Measles non-Rubella discarded rate. In 2023, non-Measles non-Rubella discard rate to date is at 0.46. (5) The B3 Measles genotype has been detected in West Kalimantan and East Java, which is not originally endemic to Indonesia.
Measles is preventable by vaccination, which provides lifelong immunity in most recipients. In countries with low vaccination coverage, epidemics may occur every two to three years. However, their duration varies according to population size, crowding, and the population's immunity status.
The measles vaccine has been in use for nearly 60 years. It is safe, effective, and inexpensive. Vaccination is recommended for all susceptible children and adults for whom the vaccine is not contraindicated. National immunization programs must ensure the safe provision of immunization services that can reach all children with two doses of the Measles vaccine. Routine Measles vaccination for children and mass immunization campaigns in countries with high case and death rates are key public health strategies to reduce global Measles deaths.
The World Health Organization recommends maintaining sustained homogeneous coverage of at least 95% with the first and second doses of the Measles vaccine and strengthening integrated epidemiological surveillance of measles and rubella to achieve timely detection of all suspected cases in public, private, and social security healthcare facilities. The World Health Organization continues to strengthen the global laboratory network to ensure timely diagnosis of Measles and track the international spread of the Measles Viruses to allow a more coordinated country approach in targeting vaccination activities and reducing deaths from this vaccine-preventable disease.
It is critical to quickly recognize and treat Measles complications to reduce the disease’s severity and mortality. Severe complications from measles can be reduced through supportive care that ensures good nutrition, adequate fluid intake, and treatment of dehydration with World Health Organization-recommended oral rehydration solution. This solution replaces fluids and other essential elements lost through diarrhoea or vomiting. Antibiotics should be prescribed to treat eye and ear infections and pneumonia.
While there is no specific antiviral treatment for Measles, prompt vitamin A in therapeutic doses is recommended to reduce complications and mortality among children infected with measles. Two doses of vitamin A oral supplements should be given 24 hours apart, irrespective of the timing of previous doses of vitamin A: 50 000 IU should be given to infants aged under 6 months, 100 000 IU to infants aged 6-11 months, and 200 000 IU to children aged 12-59 months. This treatment restores low vitamin A levels in acute measles cases that occur even in well-nourished children and can help prevent eye damage and blindness. Vitamin A supplements have also been shown to reduce the number of Measles deaths.
The World Health Organization does not recommend any restrictions on travel or trade to or from Indonesia based on the current information.
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