WHO Global Situational Alert System: a mixed methods multistage approach to identify country-level COVID-19 alerts.

BACKGROUND: Globally, since 1 January 2020 and as of 24 January 2023, there have been over 664 million cases of COVID-19 and over 6.7 million deaths reported to WHO. WHO developed an evidence-based alert system, assessing public health risk on a weekly basis in 237 countries, territories and areas from May 2021 to June 2022. This aimed to facilitate the early identification of situations where healthcare capacity may become overstretched. METHODS: The process involved a three-stage mixed methods approach. In the first stage, future deaths were predicted from the time series of reported cases and deaths to produce an initial alert level. In the second stage, this alert level was adjusted by incorporating a range of contextual indicators and accounting for the quality of information available using a Bayes classifier. In the third stage, countries with an alert level of 'High' or above were added to an operational watchlist and assistance was deployed as needed. RESULTS: Since June 2021, the system has supported the release of more than US$27 million from WHO emergency funding, over 450 000 rapid antigen diagnostic testing kits and over 6000 oxygen concentrators. Retrospective evaluation indicated that the first two stages were needed to maximise sensitivity, where 44% (IQR 29%-67%) of weekly watchlist alerts would not have been identified using only reported cases and deaths. The alerts were timely and valid in most cases; however, this could only be assessed on a non-representative sample of countries with hospitalisation data available. CONCLUSIONS: The system provided a standardised approach to monitor the pandemic at the country level by incorporating all available data on epidemiological analytics and contextual assessments. While this system was developed for COVID-19, a similar system could be used for future outbreaks and emergencies, with necessary adjustments to parameters and indicators.

The World Health Organization's public health intelligence activities during the COVID-19 pandemic response, December 2019 to December 2021.

The coronavirus disease (COVID-19) presented a unique opportunity for the World Health Organization (WHO) to utilise public health intelligence (PHI) for pandemic response. WHO systematically captured mainly unstructured information (e.g. media articles, listservs, community-based reporting) for public health intelligence purposes. WHO used the Epidemic Intelligence from Open Sources (EIOS) system as one of the information sources for PHI. The processes and scope for PHI were adapted as the pandemic evolved and tailored to regional response needs. During the early months of the pandemic, media monitoring complemented official case and death reporting through the International Health Regulations mechanism and triggered alerts. As the pandemic evolved, PHI activities prioritised identifying epidemiological trends to supplement the information available through indicator-based surveillance reported to WHO. The PHI scope evolved over time to include vaccine introduction, emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, unusual clinical manifestations and upsurges in cases, hospitalisation and death incidences at subnational levels. Triaging the unprecedented high volume of information challenged surveillance activities but was managed by collaborative information sharing. The evolution of PHI activities using multiple sources in WHO's response to the COVID-19 pandemic illustrates the future directions in which PHI methodologies could be developed and used.

Progress Toward Measles Elimination - Nepal, 2007-2014.

In 2013, the 66th session of the Regional Committee of the World Health Organization (WHO) South-East Asia Region (SEAR) established a goal to eliminate measles and to control rubella and congenital rubella syndrome (CRS) in SEAR by 2020. Current recommended measles elimination strategies in the region include 1) achieving and maintaining ≥95% coverage with 2 doses of measles-containing vaccine (MCV) in every district, delivered through the routine immunization program or through supplementary immunization activities (SIAs); 2) developing and sustaining a sensitive and timely measles case-based surveillance system that meets minimum recommended performance indicators; 3) developing and maintaining an accredited measles laboratory network; and 4) achieving timely identification, investigation, and response to measles outbreaks. In 2013, Nepal, one of the 11 SEAR member states, adopted a goal for national measles elimination by 2019. This report updates a previous report and summarizes progress toward measles elimination in Nepal during 2007-2014. During 2007-2014, estimated coverage with the first MCV dose (MCV1) increased from 81% to 88%. Approximately 3.9 and 9.7 million children were vaccinated in SIAs conducted in 2008 and 2014, respectively. Reported suspected measles incidence declined by 13% during 2007-2014, from 54 to 47 cases per 1 million population. However, in 2014, 81% of districts did not meet the measles case-based surveillance performance indicator target of ≥2 discarded non-measles cases per 100,000 population per year. To achieve and maintain measles elimination, additional measures are needed to strengthen routine immunization services to increase coverage with MCV1 and a recently introduced second dose of MCV (MCV2) to ≥95% in all districts, and to enhance sensitivity of measles case-based surveillance by adopting a more sensitive case definition, expanding case-based surveillance sites nationwide, and ensuring timely transport of specimens to the accredited national laboratory.

Progress Toward Measles Elimination - South-East Asia Region, 2003-2013.

In 2013, the 66th session of the Regional Committee of the World Health Organization (WHO) South-East Asia Region adopted the goal of measles elimination and rubella and congenital rubella syndrome control by 2020 after rigorous prior consultations. The recommended strategies include 1) achieving and maintaining ≥95% coverage with 2 doses of measles- and rubella-containing vaccine in every district through routine or supplementary immunization activities (SIAs); 2) developing and sustaining a sensitive and timely case-based measles surveillance system that meets recommended performance indicators; 3) developing and maintaining an accredited measles laboratory network; and 4) achieving timely identification, investigation, and response to measles outbreaks. This report updates previous reports and summarizes progress toward measles elimination in the South-East Asia Region during 2003-2013. Within the region, coverage with the first dose of a measles-containing vaccine (MCV1) increased from 67% to 78%; an estimated 286 million children (95% of the target population) were vaccinated in SIAs; measles incidence decreased 73%, from 59 to 16 cases per million population; and estimated measles deaths decreased 63%. To achieve measles elimination in the region, additional efforts are needed in countries with <95% 2-dose routine MCV coverage, particularly in India and Indonesia, to strengthen routine immunization services, conduct periodic high-quality SIAs, and strengthen measles case-based surveillance and laboratory diagnosis of measles.

Update on polio eradication in the World Health Organization South-East Asia Region, 2013.

There has been a tremendous amount of progress toward polio eradication in the World Health Organization South-East Asia Region particularly over the past 4 years. In 1988, there were >25,000 reported cases of wild poliovirus infection in the South-East Asia Region, and because of substantial underreporting the estimated polio burden was probably 10-fold higher. Following the initiation of mass polio immunization campaigns in the mid-1990s and years of intense effort, the 11 countries of the South-East Asia Region reported no cases of wild poliovirus infection in 2012. With India reporting the last wild poliovirus case in the region, on 13 January 2011, and its subsequent removal from the list of polio-endemic countries, in February 2012, the South-East Asia Region is firmly on track for polio-free certification in early 2014.

Estimation of the impact of a Japanese encephalitis immunization program with live, attenuated SA 14-14-2 vaccine in Nepal.

Wider availability of the live, attenuated SA 14-14-2 Japanese encephalitis (JE) vaccine has facilitated introduction or expansion of immunization programs in many countries. However, information on their impact is limited. In 2006, Nepal launched a JE immunization program, and by 2009, mass campaigns had been implemented in 23 districts. To describe the impact, we analyzed surveillance data from 2004 to 2009 on laboratory-confirmed JE and clinical acute encephalitis syndrome (AES) cases. The post-campaign JE incidence rate of 1.3 per 100,000 population was 72% lower than expected if no campaigns had occurred, and an estimated 891 JE cases were prevented. In addition, AES incidence was 58% lower, with an estimated 2,787 AES cases prevented, suggesting that three times as many disease cases may have been prevented than indicated by the laboratory-confirmed JE cases alone. These results provide useful information on preventable JE disease burden and the potential value of JE immunization programs.

Developing rubella vaccination policy in Nepal--results from rubella surveillance and seroprevalence and congenital rubella syndrome studies.

BACKGROUND: The Government of Nepal is interested in preventing congenital rubella syndrome (CRS). Surveillance data were analyzed and studies conducted to assess the burden of rubella and CRS and aid in developing a rubella vaccination strategy. METHODS: (1) Analysis of rubella cases reported through measles surveillance, 2004-2009; (2) in 2008, rubella seroprevalence among women 15 to 39 years of age was evaluated; and (3) in 2009, children attending a school for the deaf were examined for ocular defects associated with CRS. RESULTS: From 2004-2009, there were 3,710 confirmed rubella cases and more than 95% of these cases were less than 15 years of age. Of 2,224 women of childbearing age (WCBA) tested for anti-rubella IgG, 2,020 (90.8%) were seropositive. Using a catalytic infection model, approximately 1,426 infants were born with CRS (192/100,000 live births) in 2008. Among 243 students attending a school for the deaf, 18 (7.4%) met the clinical criteria for CRS. CONCLUSIONS: Rubella and CRS were documented as significant public health problems in Nepal. A comprehensive approach is necessary, including introducing rubella vaccine in the routine program, assuring immunity among WCBA, strengthening routine immunization, integrating rubella surveillance with measles case-based surveillance, and establishing CRS surveillance.

Laboratory-based Japanese encephalitis surveillance in Nepal and the implications for a national immunization strategy.

We report on two years of Japanese encephalitis (JE) surveillance in Nepal and the implications for a national immunization strategy. From May 2004 to April 2006, 4,652 patients with encephalitis were evaluated. A serum or cerebrospinal fluid specimen was collected from 3198 (69%) patients of which 1,035 (32%) were positive by Japanese encephalitis IgM ELISA. Most cases (N = 951, 92%) were from the 24 Terai districts (i.e., southern plains, 12.3 million persons) with the majority (N = 616, 65%) from four western Terai districts (population = 1.8 million). The case fatality ratio was 14.7% and 6.3% and the proportion of cases under 15 years old was 52% and 62% in the four western and 20 non-western Terai districts, respectively. Japanese encephalitis immunization targeting residents one year of age and older in the western districts and one through 14 years old in the non-western Terai districts may have reduced Japanese encephalitis cases by 84% and deaths by 92%, nationally.

Endemic Japanese encephalitis in the Kathmandu valley, Nepal.

Japanese encephalitis (JE) is endemic in the Terai region of Nepal. There is little information on the occurrence of JE outside the Terai and particularly in the densely populated Kathmandu valley. Acute encephalitis syndrome (AES) cases were detected using a sentinel surveillance system that has been functioning since 2004. JE was confirmed using anti-JE IgM ELISA. All laboratory-confirmed JE cases that occurred in the Kathmandu valley during 2006 were followed up for verification of residence and travel history. JE was confirmed in 40 residents of the Kathmandu valley, including 30 cases that had no history of travel outside the valley during the incubation period. Incidence was 2.1/100,000 and the case fatality was 20% (8/40). Currently, JE prevention is focused on the Terai region in Nepal; given the evidence, this should be reviewed for the possible inclusion of the Kathmandu valley in the national JE prevention and control program.