The need for stronger, sustainably financed adult immunization platforms and associated monitoring systems to enhance life-course vaccination benefits and to support future outbreak, epidemic, and pandemic responses is underscored.
Abstract
COVID-19 vaccination helped change the course of the pandemic and remains critical for protecting high-risk groups. We analyzed data submitted to WHO to describe COVID-19 vaccination coverage during the emergency period from 2021-2023 and annual uptake in 2024, the first post-emergency calendar year after the Public Health Emergency of International Concern designation was lifted. By end-2023, global complete primary series coverage reached 65% in the total population, 82% among older adults, and 91% among health and care workers (HCWs), across reporting countries. Booster coverage was lower, at 33%, 60%, and 69%, respectively. Across indicators, disparities by country income group and region emerged early and persisted through 2024. In 2024, vaccination of older adults and HCWs was limited and heterogeneous. These findings underscore the need for stronger, sustainably financed adult immunization platforms and associated monitoring systems to enhance life-course vaccination benefits and to support future outbreak, epidemic, and pandemic responses.
Background: Maintaining routine health services during public health emergencies is essential for health system resilience. The COVID-19 pandemic disrupted immunization services worldwide, increasing concerns about declining vaccine coverage, zero-dose children, and resurgence of vaccine-preventable diseases. Evidence from Pakistan using administrative surveillance data remains limited.
Objective: To describe temporal changes in routine immunization coverage among children aged under 24 months across pre-COVID-19, intra-COVID-19, and post-COVID-19 periods in Khyber Pakhtunkhwa, Pakistan.
Methodology: A retrospective descriptive ecological study was conducted using aggregated secondary data from the Expanded Programme on Immunization Management Information System. Immunization records from all 28 reporting districts of Khyber Pakhtunkhwa from January 2019 to April 2022 were analyzed across three periods: pre-COVID-19, January 2019–February 2020; intra-COVID-19, March 2020–September 2021; and post-COVID-19, October 2021–April 2022.
Results: Routine immunization coverage indicators demonstrated variation across the study periods. The proxy indicator for fully immunized children increased from 74% during the pre-COVID-19 period to 88% during the post-COVID-19 period, while the proportion of zero-dose children declined from 16% to 4%. Coverage for the major vaccine antigens also increased during the post-pandemic period, although BCG coverage exceeded 100%, reflecting administrative denominator limitations and programmatic factors rather than true population coverage.
Conclusion: Routine immunization indicators derived from administrative surveillance data demonstrated improved programmatic coverage during the post-COVID-19 period in Khyber Pakhtunkhwa. These findings describe temporal patterns in routine immunization service delivery within a provincial immunization programme during and after the COVID-19 pandemic and provide evidence that may inform immunization programme planning and health system preparedness for future public health emergencies. The results should be interpreted in the context of aggregated administrative data and do not imply causal relationships between programme interventions and observed coverage changes.
Keywords: Administrative Data, COVID-19, Ecological Study, Expanded Programme on Immunization, Health Systems, Khyber Pakhtunkhwa, Pakistan, Routine Immunization.
Imran Khan, Naveed Sadiq· Journal of Saidu Medical Col...· 0 citations
Background The coronavirus disease (COVID-19) vaccination campaign in South Africa constituted the most significant public health intervention in recent history, occurring against the backdrop of a prevailing quadruple burden of disease. Aim To evaluate the implementation of the COVID-19 vaccination campaign, focusing on rollout speed and geographic equity and to examine the temporal associations between vaccination coverage and mortality trends. Setting All South African residents aged 12 years and older who were eligible for COVID-19 vaccination during the study period. Methods A retrospective, ecological population-based time-series analysis to assess vaccination rollout trends and geographic equity, and to examine the association between vaccination coverage and excess mortality. The Logic Model and the RE-AIM (Reach, Effectiveness, Adoption, Implementation and Maintenance) framework were applied to interpret implementation performance. Results The vaccination campaign expanded rapidly in the early phases, but vaccination activity declined significantly over a three-year period (p < 0.001). By February 2024, approximately 49.7% of the eligible population had received at least one dose, below the national target of 67%. Coverage was higher in metropolitan than in district municipalities (p < 0.05). Statistically significant non-causal temporal associations were observed between vaccination coverage and excess mortality. Conclusion Early vaccine coverage was achieved, but uptake was insufficient to meet national coverage targets. Geographic disparities suggest potential inequities in access, offering empirical insights to strengthen primary health care integration, equitable service delivery, and data-driven implementation strategies. Contribution This study supports dual-framework implementation science for evaluating large-scale public health interventions to inform health system strengthening and emergency preparedness.
Ilona Matthew, M. Viljoen, Jane McCartney· African Journal of Primary H...· 0 citations
On March 2nd, 2021, Ghana, the first country to receive vaccines from the COVAX facility, began its COVID-19 vaccination using a complex multi-phased approach, to reach target populations. We evaluated the vaccine deployment to document best practices challenges and lessons for future new vaccine introductions and public health emergency readiness.
We conducted a mixed methods post-introduction evaluation, purposively sampling 36 facilities from 12 districts in six regions. Adapting the World Health Organization’s COVID-19 Post-Introduction Evaluation tool, we conducted a cross-sectional survey using a structured questionnaire, reviewed programme records, observed practices, and interviewed purposively selected health workers, immunization managers and partners who supported vaccine deployment. We performed summary descriptive statistics on quantitative data, thematic analysis on qualitative data, and triangulated the results.
As of March 2023, more than 70% of the target population (15 years and older) had received at least one dose, while more than 50% had completed the primary series. Vaccine deployment was built on the existing immunisation programme and functional coordinating bodies. Cold chain capacity was revamped with ultra-low-temperature freezers, while 33.3% of surveyed districts adjusted waste disposal systems to accommodate COVID-19 vaccine introduction. Door-to-door delivery and demand generation through varied risk communication and community engagement strategies improved vaccine access. Electronic data platforms were established, surge capacity improved, and healthcare and community workers were trained. Initial unpredictable vaccine supplies limited vaccination efforts. Changing vaccine information affected health workers’ ability to engage communities with up-to-date guidance. While vaccine safety monitoring systems were in place, reporting knowledge varied among health workers, and 36% of surveyed facilities had ever documented and reported COVID-19 vaccine-related adverse events following immunisation. Challenges with electronic data systems limited timely access to and use of granular service-delivery data for decision-making.
Ghana leveraged existing immunisation and emergency-response systems to make substantial progress in COVID-19 vaccine deployment. Coordination, cold chain expansion, flexible service delivery, demand generation and workforce mobilisation supported implementation. Irregular vaccine supply, data system challenges, variable adverse event reporting, waste management pressure and misinformation challenged deployment. These findings provide lessons for adult immunisation, life-course vaccination and future public health emergency readiness.
K. Amponsa-Achiano, Angela K. Shen, Eunice Baiden Laryea et al.· BMC Public Health· 0 citations
Introduction. By the end of 2023, many low-income countries had not reached 50% COVID-19 vaccine coverage, while most high-income countries had exceeded 80%. It remains unclear whether receiving vaccine deliveries translated into faster population coverage. We examined cross-national inequalities in the timing of the vaccine rollout and whether deliveries through the COVID-19 Vaccines Global Access (COVAX) facility were associated with subsequent national uptake. Methods. We conducted an observational study of 218 countries and territories using country-level data up to December 2023. We used generalized additive mixed models to identify country-level correlates of coverage at an early and a later stage of the pandemic, survival analysis to compare the time to 50% coverage between COVAX Advance Market Commitment (AMC) and non-AMC countries, and an event study to estimate the association between the timing of the first COVAX delivery and subsequent monthly coverage in AMC countries. Results. AMC-supported countries reached 50% coverage substantially more slowly than non-AMC countries. The hazard of reaching the threshold was 0.17 times that of non-AMC countries at month 1 (95% CI 0.07 to 0.41) and 0.53 times at month 18 (95% CI 0.33 to 0.85). One year after rollout began, 65.9% of AMC countries (95% CI 56.7 to 76.6) had not reached 50% coverage, compared with 21.1% of non-AMC countries (95% CI 15.1 to 29.5). The timing of COVAX deliveries was not significantly associated with subsequent national uptake in any post-delivery month. In the early stage of rollout, higher maternal mortality was associated with lower coverage, while a larger urban population was associated with higher coverage. By the end of the observation period, larger household size was associated with lower coverage, while higher health expenditure and a larger urban population were associated with higher coverage. Conclusion. Receiving COVAX deliveries was not, on its own, associated with faster coverage. Coverage differences were more consistently associated with country-level structural and health-system characteristics, while we found no significant association with the timing of the first COVAX delivery. Achieving vaccine equality likely requires strengthening the capacity of health systems to convert deliveries into administered doses, and preparedness efforts should invest in last-mile delivery capacity ahead of future emergencies.
H.-W. Lee, Y.-H. Huang, T. McAndrew· medRxiv· 0 citations
Background/Objectives: This study evaluated changes in routine adult vaccination across the COVID-19 pandemic period in Istanbul primary care using interrupted time series (ITS) analysis, disentangling immediate from gradual effects and comparing patterns across socioeconomically distinct centers, through a multicenter retrospective analysis of routine (non-COVID-19 vaccination records). Methods: The full descriptive dataset comprised 33,016 adult vaccination records. After excluding 25,805 COVID-19 vaccination records, 7211 routine (non-COVID-19) vaccination records from nine family medicine units in three Istanbul training family health centers—Şişli-Gülbahar, Kağıthane, and Gaziosmanpaşa—were included in the routine vaccine and ITS analyses and were analyzed over 97 monthly observations (June 2017–August 2025), divided into three 672-working-day periods: pre-pandemic, pandemic, and post-pandemic. Segmented negative binomial ITS regression with a log (working days) offset was the primary analysis; Newey-West HAC-robust Poisson regression served as sensitivity analysis. Catchment districts were characterized using the 2022 Socioeconomic Development Ranking (SEGE-2022). Results: No significant immediate level change occurred in total routine vaccination at pandemic onset. Pneumococcal vaccination showed the most pronounced signal: an upward pretrend (annual slope IRR = 2.583; p = 0.001), a level increase at onset (IRR = 3.589; p = 0.013), then a rapid within-pandemic slope decline (annual slope IRR = 0.227; p < 0.001). Tetanus-diphtheria (Td) vaccination fell sharply at onset (IRR = 0.686; p = 0.002) and continued declining post-pandemic (annual slope IRR = 0.805; p = 0.008). Versus Gaziosmanpaşa (rank 85/973), Kağıthane (rank 38) showed the highest total routine vaccination rate (excluding COVID-19 vaccination) (IRR = 1.539; p < 0.001), exceeding Şişli (rank 1; IRR = 1.269; p < 0.001). Conclusions: Changes in routine adult vaccination across the pandemic period were vaccine-specific: pneumococcal vaccination surged then declined; Td vaccination showed continued post-pandemic decline. Center-level vaccination patterns were not consistently aligned with district-level socioeconomic ranking.
Begüm Yıldırım Erence, Feyzanur Erdem, Ebru Tepe et al.· Vaccines· 0 citations
The CDC’s COVID-19 pandemic guidelines affected everyone, especially healthcare workers (HCWs) due to the high exposure risks, long hours and stress during the pandemic. Thus, understanding HCWs perceptions and acceptance of these guidelines were crucial to patient outcomes. Our goal was to investigate HCWs views on the Centers for Disease Control and Prevention (CDC) management of the COVID-19 pandemic and vaccine recommendations. Data were collected from an online survey of HCWs in Pennsylvania (August 2022 – February 2023). Eligible participants (n = 580) aged 21 + , reported COVID-19 vaccination status and time of first vaccination. Participants (n = 580) were 83% female and 92% White. From our sample, 71% provided direct care, 57% lived in a suburban area, and 85% had received at least one dose of the vaccine. HCWs had mixed perceptions of the CDC’s management of the COVID-19 pandemic and vaccine recommendations. Positive perceptions of pandemic management highlighted clear communication, a science-driven approach, and an effective crisis response. Criticisms included overregulation of face mask requirements, politicization, and continuously changing policies. Regarding vaccine recommendations, positive perceptions included timely distribution, accessibility, affordability, and clear communication, while criticisms included vaccine mandates, politicization, perceived lack of scientific basis, and inconsistent messaging. Future recommendations for the CDC regarding outbreaks would be to ensure framing of messaging is free from perceived political bias. The CDC should continue to maintain communication with HCWs and focus on providing evidence-based information during future pandemics.
Gail C D'Souza-Rushton, Uttara Seshu, Liba Blumberger et al.· PLoS ONE· 0 citations
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