BACKGROUND: The COVID-19 pandemic had a profound impact on healthcare systems and services, including routine immunization (RI). To date, there is limited information on the effects of the COVID-19 pandemic on RI in West African countries such as Sierra Leone, which had already experienced public health emergencies that disrupted its healthcare system. Here, we describe the impact of the COVID-19 pandemic on the RI of key antigens in Sierra Leone.
METHODS: We used vaccination data from the District Health Information System for BCG, measles-rubella 1 and 2, and pentavalent 1 and 3 antigens. We compared 2019, 2020, 2021, and 2022 annual coverage rates for the selected antigens at the national and district levels. We used the Pearson chi-square test to assess the difference between annual coverage rates between 2019 and 2020, 2020-2021, and 2021-2022.
RESULTS: National coverage rates for all antigens declined in 2019-2020, notably measles-rubella 1 and pentavalent 3 (-5.4% and - 4.9%). Between 2020 and 2021, there was an overall increase in coverage (+ 0.2% to + 2.5%), except for measles-rubella 2 (-1.8%). Measles-rubella antigens rebounded in 2021-2022, while others decreased between - 0.5 and - 1.9% in coverage. Overall, all district-level coverage rates in 2022 were lower than those in 2019. Most districts decreased between 2019 and 2022, though a few had a continuous increase; some had an increase/recovery between 2020 and 2021; some districts had recovered 2019 levels by 2022.
CONCLUSIONS: The COVID-19 pandemic impacted Sierra Leone\'s national BCG, measles-rubella, and pentavalent antigen immunization, which were not fully restored in 2022. Most districts experienced notable coverage declines during the pandemic, though a few reached or surpassed 2019 rates in 2022. Examining pandemic impact can benefit from a focus beyond the national level to identify vulnerable regions. Sierra Leone\'s post-pandemic RI reestablishment needs targeted strategies and continual investments for equitable access and coverage, as well as to prevent vaccine-preventable diseases.

OBJECTIVE: No consensus exists about the best COVID-19 vaccination strategy to be adopted by low-income and middle-income countries. Brazil adopted an age-based calendar strategy to reduce mortality and the burden on the healthcare system. This study evaluates the impact of the vaccination campaign in Brazil on the progression of the reported COVID-19 deaths.
METHODS: This ecological study analyses the dynamic of vaccination coverage and COVID-19 deaths in hospitalised adults (≥20 years) during the first year of the COVID-19 vaccination roll-out (January to December 2021) using nationwide data (DATASUS). We stratified the adult population into 20-49, 50-59, 60-69 and 70+ years. The dynamic effect of the vaccination campaign on mortality rates was estimated by applying a negative binomial regression. The prevented and possible preventable deaths (observed deaths higher than expected) and potential years of life lost (PYLL) for each age group were obtained in a counterfactual analysis.
RESULTS: During the first year of COVID-19 vaccination, 266 153 517 doses were administered, achieving 91% first-dose coverage. A total of 380 594 deaths were reported, 154 091 (40%) in 70+ years and 136 804 (36%) from 50-59 or 20-49 years. The mortality rates of 70+ decreased by 52% (rate ratio [95% CI]: 0.48 [0.43-0.53]) in 6 months, whereas rates for 20-49 were still increasing due to low coverage (52%). The vaccination roll-out strategy prevented 59 618 deaths, 53 088 (89%) from those aged 70+ years. However, the strategy did not prevent 54 797 deaths, 85% from those under 60 years, being 26 344 (45%) only in 20-49, corresponding to 1 589 271 PYLL, being 1 080 104 PYLL (68%) from those aged 20-49 years.
CONCLUSIONS: The adopted aged-based calendar vaccination strategy initially reduced mortality in the oldest but did not prevent the deaths of the youngest as effectively as compared with the older age group. Countries with a high burden, limited vaccine supply and young populations should consider other factors beyond the age to prioritise who should be vaccinated first.

Until recently, the Thai national program of seasonal influenza vaccination for high-risk people has been using a walk-in service system. However, in 2020, an online registration system was introduced in Bangkok to improve vaccine coverage. This study aimed to compare the coverage of influenza vaccination between the walk-in service and online registration systems. The study participants included 374,710 Thai individuals who obtained an influenza vaccination from the national program in the Bangkok health region in 2018 (n = 162,214) and in 2020 (n = 212,496). The registration systems that were examined were the walk-in service system in 2018 and the online registration system in 2020. The characteristics of vaccine recipients and the vaccine coverage in each risk group and health facility level were compared between the two systems. Coverage comparison in Bangkok between the years 2018 and 2020 showed an increase in coverage, particularly among individuals who had an influenza vaccination at health facilities of the primary level and in the elderly and obesity groups. The coverage among children was lowest among all high-risk groups. To improve coverage in Thailand, the online registration system should be introduced in all regions. Additionally, information about influenza vaccination for children should be disseminated to parents using handbooks or by word-of-mouth from healthcare workers.

In 2020-21, during the COVID-19 pandemic, a free influenza vaccination program was initiated among the elderly residents in Ningbo, China. The impact of the COVID-19 pandemic and free vaccination policy on influenza vaccine uptake needs to be evaluated. The influenza vaccine uptake among individuals born before 31 December, 1962 from 2017-18 to 2022-23 season in Ningbo was analyzed. Multivariate logistic regressions were used to estimate the impact of the COVID-19 pandemic and free vaccination policy. Our analysis included an average of 1,856,565 individuals each year. Influenza vaccination coverage increased from 1.14% in 2017-18 to 33.41% in 2022-23. The vaccination coverage among the free policy target population was 50.03% in 2022-23. Multivariate analysis showed that free vaccination policy increased influenza vaccine uptake most (OR = 11.99, 95%CI: 11.87-12.11). The initial phase of the pandemic was associated with a positive effect on influenza vaccination (OR = 2.09, 95%CI: 2.07-2.12), but followed by a negative effect in the subsequent two seasons(2021-22: OR = 0.75, 95%CI: 0.73-0.76; 2022-23: OR = 0.40, 95%CI: 0.39-0.40). COVID-19 vaccination in the current season was a positive predictor of influenza vaccine uptake while not completing booster COVID-19 vaccination before was negative predictor in 2022-23. Having influenza vaccine history and having ILI medical history during the last season were also positive predictors of influenza vaccine uptake. Free vaccination policies have enhanced influenza vaccination coverage among elderly population. The COVID-19 pandemic plays different roles in different seasons. Our study highlights the need for how to implement free vaccination policies targeting vulnerable groups with low vaccination coverage.

BACKGROUND: The aim of this review was to investigate the impact of short message service (SMS)-based interventions on childhood and adolescent vaccine coverage and timeliness.
METHODS: A pre-defined search strategy was used to identify all relevant publications up until July 2022 from electronic databases. Reports of randomised trials written in English and involving children and adolescents less than 18 years old were included. The review was conducted in accordance with PRISMA guidelines.
RESULTS: Thirty randomised trials were identified. Most trials were conducted in high-income countries. There was marked heterogeneity between studies. SMS-based interventions were associated with small to moderate improvements in vaccine coverage and timeliness compared to no SMS reminder. Reminders with embedded education or which were combined with monetary incentives performed better than simple reminders in some settings.
CONCLUSIONS: Some SMS-based interventions appear effective for improving child vaccine coverage and timeliness in some settings. Future studies should focus on identifying which features of SMS-based strategies, including the message content and timing, are determinants of effectiveness.

BACKGROUND: Healthcare Workers (HCWs) are susceptible to hepatitis B virus (HBV) infection and are advised to receive vaccination. However, vaccination rates remain low in developing countries. There is little data concerning Hepatitis B (HepB) vaccination and information regarding HBV knowledge among HCWs in Cambodia. This study aimed to evaluate the knowledge of HBV infection, HepB vaccine, and vaccination status with its associated factors among HCWs in Cambodia.
METHODS: A Cross-sectional study was conducted among HCWs in Kampot and Kep Provinces, Cambodia, from September to October 2023 using a questionnaire survey. A total of 261 HCWs were recruited from 1,309 individuals working in all 83 health facilities using systematic random sampling methods. Statistical analyses including the χ2-test and multivariate logistic regression were conducted to identify factors associated with vaccination among the participants.
RESULTS: Among 259 participants, 62.9% showed good knowledge of HBV infection, and 65.6% demonstrated good knowledge of the HepB vaccine. 59.8% of the participants had received the HepB vaccine, while 40.2% remained unvaccinated. Analysis showed that HCWs working at Provincial Health Department/Operational Districts and Provincial Referral Hospital/Referral Hospitals were more likely to be vaccinated compared to those at Health Centers [AOR = 6.5; CI = 1.1-39.5, p = 0.0403; AOR = 2.8, CI = 1.0-7.8, p = 0.0412], respectively. Furthermore, individuals with good knowledge of the HBV infection and vaccine were more likely to receive the vaccine compared to those with inadequate knowledge [AOR = 6.3; CI = 3.3-12.3, p < .0001; AOR = 3.7, CI = 1.9-7.4, p = 0.0001], respectively. Within the unvaccinated HCWs, 32% reported high vaccine costs as a barrier, 33% mentioned workplace vaccine was not for adults, and 59% reported insufficient education on adult HepB vaccination.
CONCLUSIONS: The HepB vaccination coverage among HCWs is at 59.8%, which is below the World Health Organization\'s (WHO) recommendation rate of 100%. Knowledge of HBV infection and HepB vaccine were good predictive factors for vaccination. The high cost of vaccine, workplace vaccine not for adults, and insufficient education on adult vaccination were found as barriers to vaccination. This study underscores the importance of providing education to HCWs on HBV infection and the HepB vaccine. Furthermore, it highlights the need for a policy that ensures free vaccination for HCWs.

India has experienced tremendous progress in childhood immunization through centralized flagship programs since 1985. There is a wide variation of immunization coverage of children aged 12-23 months among Indian states and regions. The North East (NE) region, including eight sister states, has witnessed low immunization coverage (68.4%) with higher dropouts (25%) and nonvaccinations (7.0%). NE Indian states substantially improved childhood immunization from 22.8% in 1992-93 to 68.4% in 2019-2021; still, it is below the national average (77%) and the lowest among the Indian States/UTs. Highly predictive determinants for the outcome of childhood vaccination status include maternal characteristics antenatal care for pregnancy, place of delivery, education level, and media exposure. A large section of the backward hilly tribes is also needed special attention to improving the levels of childhood vaccinations in NE states.

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Cervical cancer is the fourth most common cancer, with 99% of cases linked to human papillomavirus (HPV) infection. It reflects global inequity as its burden is highest in low- and middle-income countries. The aim of this study was to determine the HPV vaccination coverage and its determinant factors among young women in the three sub-Saharan African countries. Data from the Demographic and Health Surveys among three sub-Saharan African countries were used for analysis. A total of 4,952 women were included in the study. Stata 14 was used to analyze the data. The determinants of the outcome variable were identified using a multilevel mixed-effects logistic regression model. Factors with p-values < 0.05 at 95% confidence interval were declared statistically significant. About 7.5% young women were vaccinated for HPV vaccine against cervical cancer in the current study. Younger age, use of internet, rich economic class, and individual-level media exposure were found to be favorable conditions, whereas being employed was negatively associated with HPV vaccination. Only few segments of young women in these three countries got HPV vaccination. The authors recommend that increasing internet use, media exposure, and economic level of young women will increase the HPV vaccination rates. Furthermore, creating awareness among employed women will also increase the possibility of HPV vaccination.

Since the launch of the Global Polio Eradication Initiative in 1988, substantial progress has been made in the interruption of wild poliovirus (WPV) transmission worldwide: global eradication of WPV types 2 and 3 were certified in 2015 and 2019, respectively, and endemic transmission of WPV type 1 continues only in Afghanistan and Pakistan. After the synchronized global withdrawal of all serotype 2 oral poliovirus vaccines (OPVs) in 2016, widespread outbreaks of circulating vaccine-derived poliovirus type 2 (cVDPV2) have occurred, which are linked to areas with low population immunity to poliovirus. Officials in Somalia have detected ongoing cVDPV2 transmission since 2017. Polio vaccination coverage and surveillance data for Somalia were reviewed to assess this persistent transmission. During January 2017-March 2024, officials in Somalia detected 39 cVDPV2 cases in 14 of 20 regions, and transmission has spread to neighboring Ethiopia and Kenya. Since January 2021, 28 supplementary immunization activities (SIAs) targeting cVDPV2 were conducted in Somalia. Some parts of the country are security-compromised and inaccessible for vaccination campaigns. Among 1,921 children with nonpolio acute flaccid paralysis, 231 (12%) had not received OPV doses through routine immunization or SIAs, 95% of whom were from the South-Central region, and 60% of whom lived in inaccessible districts. Enhancing humanitarian negotiation measures in Somalia to enable vaccination of children in security-compromised areas and strengthening campaign quality in accessible areas will help interrupt cVDPV2 transmission.