Insights from a modelling analysis of COVID-19 vaccination in the Eastern Mediterranean Region.

Background: Understanding the main determinants of COVID-19 vaccine uptake is critical to increasing vaccine coverage. This is particularly important for COVID-19 vaccine uptake, which has been affected by both demand and supply issues. Aim: To understand the links between vaccine uptake and demand and supply issues in the WHO Eastern Mediterranean and UNICEF Middle East and North Africa regions. Methods: We collected data through 2 rounds of a repeated cross-sectional phone survey from 11 000 individuals across 16 low- and middle-income countries. We used logit modelling to distil the main characteristics of the 4 vaccination categories (vaccinated, unvaccinated but willing, unvaccinated and undecided, and unvaccinated and unwilling) while also considering vaccine availability. We conducted sub-regional analysis to account for differences in level of development between the low- and middle-income countries. Results: Despite the increase in vaccination coverage from 60.9% at the end of 2021 to 78.3% by August 2022, about 9% were not willing and were not vaccinated during the two rounds of interviews. Our modelling analysis revealed that positive beliefs about safety, effectiveness and side effects of the COVID-19 vaccines were associated with increased odds of being vaccinated or willingness to be vaccinated. Those who did not believe in the safety of the vaccines were less likely to be vaccinated than those who believed in the safety of the vaccines (OR: 0.56; 95% CI: 0.46-0.67). By contrast, negative beliefs about the COVID-19 vaccines increased the probability of being unwilling to be vaccinated. Conclusion: The results from this research offer useful insights into tackling the supply and demand related barriers to COVID-19 vaccination uptake and provides lessons for future health threats.

Concurrent outbreaks of circulating vaccine-derived poliovirus types 1 and 2 affecting the Republic of the Philippines and Malaysia, 2019-2021.

Concurrent outbreaks of circulating vaccine-derived poliovirus serotypes 1 and 2 (cVDPV1, cVDPV2) were confirmed in the Republic of the Philippines in September 2019 and were subsequently confirmed in Malaysia by early 2020. There is continuous population subgroup movement in specific geographies between the two countries. Outbreak response efforts focused on sequential supplemental immunization activities with monovalent Sabin strain oral poliovirus vaccine type 2 (mOPV2) and bivalent oral poliovirus vaccines (bOPV, containing Sabin strain types 1 and 3) as well as activities to enhance poliovirus surveillance sensitivity to detect virus circulation. A total of six cVDPV1 cases, 13 cVDPV2 cases, and one immunodeficiency-associated vaccine-derived poliovirus type 2 case were detected, and there were 35 cVDPV1 and 31 cVDPV2 isolates from environmental surveillance sewage collection sites. No further cVDPV1 or cVDPV2 have been detected in either country since March 2020. Response efforts in both countries encountered challenges, particularly those caused by the global COVID-19 pandemic. Important lessons were identified and could be useful for other countries that experience outbreaks of concurrent cVDPV serotypes.

Health and immunisation services for the urban poor in selected countries of Asia.

BACKGROUND: Asia is a region that is rapidly urbanising. While overall urban health is above rural health standards, there are also pockets of deep health and social disadvantage within urban slum and peri-urban areas that represent increased public health risk. With a focus on vaccine preventable disease and immunisation coverage, this commentary describes and analyses strengths and weaknesses of existing urban health and immunisation strategy, with a view to recommending strategic directions for improving access to immunisation and related maternal and child health services in urban areas across the region. The themes discussed in this commentary are based on the findings of country case studies published by the United Nations Childrens Fund (UNICEF)  on the topic of immunisation and related health services for the urban poor in Cambodia, Indonesia, Mongolia, Myanmar, the Philippines, and Vietnam. MAIN BODY: Although overall urban coverage is higher than rural coverage in selected countries of Asia, there are also wide disparities in coverage between socio economic groups within urban areas. Consistent with these coverage gaps, there is emerging evidence of outbreaks of vaccine preventable diseases in urban areas. In response to this elevated public health risk, there have been some promising innovations in operational strategy in urban settings, although most of these initiatives are project related and externally funded. Critical issues for attention for urban health services access include reaching consensus on accountability for management and resourcing of the strategy, and inclusion of an urban poor approach within the planning and budgeting procedures of Ministries of Health and local governments. Advancement of local partnership and community engagement strategies to inform operational approaches for socially marginalised populations are also urgently required. Such developments will be reliant on development of municipal models of primary health care that have clear delegations of authority, adequate resources and institutional capabilities to implement. CONCLUSIONS: The development of urban health systems and immunisation strategy is required regionally and nationally, to respond to rapid demographic change, social transition, and increased epidemiological risk.

Experience With Inactivated Polio Vaccine Introduction and the "Switch" From Trivalent to Bivalent Oral Polio Vaccine in the World Health Organization's Western Pacific Region.

The World Health Organization (WHO) Western Pacific Region (WPR) has maintained its polio-free status since 2000. The emergence of vaccine-derived polioviruses (VDPVs), however, remains a risk, as oral polio vaccine (OPV) is still used in many of the region's countries, and pockets of unimmunized or underimmunized children exist in some countries. From 2014 to 2016, the region participated in the globally coordinated efforts to introduce inactivated polio vaccine (IPV) into all countries that did not yet include it in their national immunization schedules, and to "switch" from trivalent OPV (tOPV) to bivalent OPV (bOPV) in all countries still using OPV in 2016.As of September 2016, 15 of 17 countries and areas that did not use IPV by the end of 2014 had introduced IPV. Introduction in the remaining 2 countries has been delayed because of the global shortage of IPV, making it unavailable to select lower-risk countries until the fourth quarter of 2017. All 16 countries using OPV as of 2016 successfully withdrew tOPV during the globally synchronized switch from April to May 2016, and 15 of 16 countries introduced bOPV at the same time, with the remaining country introducing it within 30 days. While countries were primarily responsible for self-funding these activities, additional support was provided.The main challenges encountered in the Western Pacific Region with both IPV introduction and the tOPV-bOPV switch were related to overcoming regulatory policies and challenges with vaccine procurement. As a result, substantial lead time was needed to resolve procurement and regulatory issues before the introductions of IPV and bOPV. As the global community prepares for the full removal of all OPV from immunization programs, this need for lead time and consideration of the impact on national policies should be considered.

The Switch From Trivalent to Bivalent Oral Poliovirus Vaccine in the South-East Asia Region.

This analysis describes an innovative and successful approach to risk identification and mitigation in relation to the switch from trivalent to bivalent oral polio vaccine (OPV) in the 11 countries of the World Health Organization's (WHO's) South-East Asia Region (SEAR) in April 2016.The strong commitment of governments and immunization professionals to polio eradication and an exemplary partnership between the WHO, United Nations Children's Fund (UNICEF), and other partners and stakeholders in the region and globally were significant contributors to the success of the OPV switch in the SEAR. Robust national switch plans were developed and country-specific innovations were planned and implemented by the country teams. Close monitoring and tracking of the activities and milestones through dashboards and review meetings were undertaken at the regional level to ensure that implementation time lines were met, barriers identified, and solutions for overcoming challenges were discussed and implemented.The SEAR was the first WHO Region globally to complete the switch and declare the successful withdrawal of trivalent OPV from all countries on 17 May 2016.A number of activities implemented during the switch process are likely to contribute positively to existing immunization practices and to similar initiatives in the future. These activities include better vaccine supply chain management, improved mechanisms for disposal of vaccination-related waste materials, and a closer collaboration with drug regulators, vaccine manufacturers, and the private sector for immunization-related initiatives.