Vaccination Delay Research Articles

The burden of vaccine hesitancy for routine immunization in Yaounde-Cameroon: A cross-sectional study.

Immunization is the most cost-effective health intervention in the world yet, vaccination uptake is still low with less than 50% of children aged 12-23 months fully vaccinated in Cameroon by 2018. The objective of this study was to estimate the burden of vaccine hesitancy associated with routine vaccines in Yaounde-Cameroon. A two-stage cross-sectional cluster survey was conducted in Yaoundé in November 2021, targeting parents/guardians of children 0-59 months. Clusters were selected with probability proportionate to size (PPS) and household's selection done using a restricted sampling method. Data collection was done using an interviewer-administered questionnaire, "Core Closed Questions" and "Likert Scale Questions" proposed by the WHO Vaccine Hesitancy Technical Working Group in 2014. Vaccine hesitancy was analyzed as proportions of parent's/guardian's self-reported vaccine refusal or delay in vaccination with 95% confidence interval. This was stratified by household wealth level and tested using Chi-Square test to appreciate the effect of household wealth on vaccine hesitancy. A total of 529 participants were enrolled out of 708 visited, giving a non-response rate of 25%. In total, vaccine hesitancy was reported in 137(25.90[22.35-29.80] %), and oral polio vaccine(OPV) was the most affected vaccine with hesitancy of 10%. Vaccine hesitancy prevalence did not vary significantly across different households' wealth levels (p-value = 0.3786). However, in wealthy households' refusal of vaccines (14%) was less than in poorer households (20%). Lack of trust was reported as the leading cause of vaccine refusal (43%). Vaccine hesitancy prevalence in Yaounde is high and oral polio vaccine(OPV) was the most affected vaccine. The level of weath does not affect vaccine hesitancy and lack of trust was the leading cause of vaccine hesitancy related to routine immunization in Yaounde-Cameroon. We, recommend that the burden of vaccine hesitancy should be assessed at national scale and root causes investigated.

Global stability and optimal control for a COVID-19 model with vaccination and isolation delays

COVID-19 pandemic remains serious around the world and causes huge deaths and economic losses. To investigate the effect of vaccination and isolation delays on the transmission of COVID-19, we propose a mathematical model of COVID-19 transmission with vaccination and isolation delays. The basic reproduction number is computed, and the global dynamics of the model are proved. When R0<1, the disease-free equilibrium is globally asymptotically stable. The unique endemic equilibrium is globally asymptotically stable if R0>1. Based on the public information, parameter values are estimated, and sensitivity analysis is carried out by the partial rank correlation coefficients (PRCCs) and the extended version of the Fourier amplitude sensitivity test (eFAST). Our results suggest that the isolation rates of asymptomatic and symptomatic infectious individuals have a significant impact on the transmission of COVID-19. When the COVID-19 is epidemic, the optimal control strategies of our model with vaccination and isolation delays are analyzed. Under the limited resource with constant and time-varying isolation rates, we find that the optimal isolation rates may minimize the cumulative number of infected individuals and the cost of disease control, and effectively contain the transmission of COVID-19. Our study may help public health to prevent and control the COVID-19 spread.

Attitudes and perceptions of mothers towards childhood vaccination in Greece: lessons to improve the childhood COVID-19 vaccination acceptance.

BackgroundMaternal attitudes and beliefs have been shown to influence childhood vaccination coverage, resulting in under-vaccination, non-vaccination, and vaccination delay. This study aimed to investigate the mothers' attitudes and perceptions about vaccination for their children in Greece.MethodsThis was an online cross-sectional study, conducted from 4 April to 8 June 2020. A self-administered questionnaire was used to collect information about mothers' and their children's socio-demographic characteristics, previous vaccination behavior, and mothers' attitudes and perceptions about childhood vaccination. Participants included adult mothers with at least one minor child.ResultsOne thousand eight hundred eighty-five mothers participated, with the majority (91.7%) believing in the usefulness of vaccines and that vaccines protect children from serious and life-threatening diseases. A larger percentage of mothers with higher educational attainment agreed/absolutely agreed that all vaccinations provided by the National Vaccination Program must be offered to their children (91.6%) (p = 0.02) and that vaccines protect children from serious and life-threatening diseases (92.9%) (p = 0.01). Significant more married/in cohabitation and not single-parent mothers agreed that vaccines are safe (53.5% and 53.4%, respectively). There were also several significant associations between maternal attitudes toward childhood vaccination and previous maternal vaccination practices [(e.g., adherence to recommended vaccination dosages (all p-values < 0.01), vaccination delays (all p-values < 0.05), and vaccination during pregnancy (all p-values < 0.01)].ConclusionMaternal attitudes and perceptions toward childhood vaccination are significantly influenced by sociodemographic factors and maternal vaccination practices. Revealing those is essential for public health officials in developing future strategies to improve childhood vaccination coverage and acceptance of new vaccines such as the COVID-19 vaccine.

COVID-19 Vaccine Willingness and Related Factors Among Health Care Workers in 3 Southeast Asian Jurisdictions

COVID-19 vaccine hesitancy is widespread and may lead to refusal or delay of vaccination, eventually reducing the overall vaccination coverage rate and vaccine effectiveness. Willingness to receive COVID-19 vaccination among health care workers (HCWs) is diverse across different jurisdictions. To assess the COVID-19 vaccine willingness among HCWs in 3 Southeast Asian jurisdictions in the context of pandemic severity and vaccination policy. A cross-sectional online survey was conducted among frontline HCWs in Hong Kong, Nepal, and Vietnam from May to November 2021. Eligible participants were nurses and doctors aged 18 and older, working in public or private health care settings on a full-time or part-time basis. The COVID-19 pandemic and vaccination policy. COVID-19 vaccination willingness was defined as HCW willingness toward receiving the COVID-19 vaccine in full course or the first dose of the vaccine, and willingness to take the second dose. Information on sociodemographic characteristics, the history of seasonal influenza vaccination, attitudes toward vaccination, and opinions on strategies associated with vaccination uptake from the study participants. Among the 3396 eligible doctors and nurses who participated in the survey, 2834 (83.4%) were from Hong Kong, 328 (9.7%) were from Nepal, and 234 (6.9%) were from Vietnam. Most respondents were female (76.2% [2589 ]), aged 30 to 39 years (31.2% [1058]), and nurse HCWs (77.6% [2636]); the response rates were 11% (2834 of 25 000) in Hong Kong, 36% (328 of 900) in Nepal, and 13% (234 of 1800) in Vietnam. Overall, the prevalence rate of willingness to take the COVID-19 vaccine was highest in Nepal (95.4% [313 of 328]), followed by Vietnam (90.6% [212 of 234]), and lowest in Hong Kong (54.4% [1542 of 2834]), relating to their different attitudes and opinions toward the COVID-19 vaccination, and the pandemic severity and vaccination policy in the 3 jurisdictions. Doctors were more willing to take COVID-19 vaccination than nurses (odds ratio, 5.28; 95% CI, 3.96-7.04). Older age (odds ratios, 1.39-3.70), male gender (odds ratio, 1.41; 95% CI, 1.11-1.75), higher educational level (odds ratio, 1.48; 95% CI, 1.17-1.87), and having seasonal influenza vaccination uptake history (odds ratio, 2.15; 95% CI, 1.82-2.54) were found to be associated with increased willingness. Choice of vaccination brand with adequate information, immunity passport, time off from work for vaccination and subsidy for travel to inconvenient vaccination centers were considered as strategies to enhance vaccine willingness. In this survey study, vaccination unwillingness existed among HCWs in Southeast Asian regions, especially in Hong Kong. The findings of this study may have utility in the formulation of vaccination promotion strategies such as vaccination incentives. Attitudes toward vaccination in HCWs might be examples for the general population; however, changes over time should be further investigated.

Examining enablers of vaccine hesitancy toward routine childhood and adolescent vaccination in Malawi

BackgroundThe contribution of vaccination to global public health and community wellbeing has been described as one of the greatest success stories of modern medicine. However, 13.5 million children still miss at least one of their routine vaccinations, and this contributes to about 1.5 million deaths from vaccine-preventable diseases. One of the contributing factors has been associated with vaccine hesitancy. Vaccine hesitancy is the delay or refusal of vaccines despite their availability. The study explored factors from multiple perspectives that influence hesitancy among caregivers of children and adolescent girls eligible for childhood routine immunisation and the Human Papillomavirus vaccine in Malawi.MethodsThe methodology used was qualitative such as key informant interviews and focus-group discussion. Information was obtained from caregivers, community and religious leaders, leaders of civil society groups, teachers in schools where Human Papillomavirus vaccine were piloted, healthcare workers, national and district-level officials of the expanded program on immunisation. There were 25 key informant interviews and two focus-group discussions, with 13 participants. The study was conducted between April to May 2020. The Interviews and discussions were audio-recorded, transcribed, and analysed using a thematic content approach.ResultsMost vaccine-hesitancy drivers for routine immunisation were also relevant for the HPV vaccine. The drivers included inadequate awareness of the vaccination schedule, rumours and conspiracy theories exacerbated by religious beliefs, low literacy levels of caregivers, distance and transport to the vaccination clinic, gender role and a disconnect between community healthcare workers and community leaders.ConclusionsThe study demonstrated that a network of factors determines vaccine hesitancy for childhood Routine Immunisation and Human Papillomavirus, and some of them are interrelated with one another. This has implications both for current levels of vaccine acceptance and the introduction of any new vaccine, such as those against Malaria, HIV/AIDS, HPV or COVID-19 (coronavirus disease 2019). Therefore, strategies developed to address vaccine hesitancy must be multi-component and wide-ranging.

Beyond coverage: Rural-urban disparities in the timeliness of childhood vaccinations in Tanzania

BackgroundTimely vaccination maximizes efficacy for preventing infectious diseases. In the absence of national vaccination registries, representative sample survey data hold vital information on vaccination coverage and timeliness. This study characterizes vaccination coverage and timeliness in Tanzania and provides an analytic template to inform contextually relevant interventions and evaluate immunization programs. MethodsCross-sectional data on 6,092 children under age 3 from the 2015–16 Tanzania Demographic and Health Survey were used to examine coverage and timeliness for 14 vaccine doses recommended in the first year of life. The Kaplan-Meier method was used to model time to vaccination. Cox proportional hazard models were used to examine factors associated with timely vaccination. ResultsSubstantial rural–urban disparities in vaccination coverage and timeliness were observed for all vaccines. Across 14 recommended doses, documented coverage ranged from 52 % to 79 %. Median vaccination delays lasted up to 35 days; gaps were larger among rural than urban children and for later doses in vaccine series. Among rural children, median delays exceeded 35 days for the 3rd doses of the polio, pentavalent, and pneumococcal vaccines. Median delays among urban children were < 21 days for all doses. Among rural and urban children, lower maternal education and delivery at home were associated with increased risk of delayed vaccination. In rural settings, less household wealth and greater distance to a health facility were also associated with increased risk of delayed vaccination. DiscussionThis study highlights persistent gaps in uptake and timeliness of childhood vaccinations in Tanzania and substantial rural–urban disparities. While the results provide an informative situation assessment and outline strategies for identifying unvaccinated children, a national electronic registry is critical for comprehensive assessments of the performance of vaccination programs. The timeliness measure employed in this study—the amount of time children are un- or undervaccinated—may serve as a sensitive performance metric for these programs.

Acceptability of COVID-19 vaccines among Black immigrants living in the United States

BackgroundCoronavirus disease 2019 (COVID-19) has disproportionately affected the Black community in the United States (U.S.). The emergency authorization of three COVID-19 vaccines in the U.S.—issued between December 2020 and February 2021—will significantly reduce hospitalizations and deaths due to COVID-19. To date, no published study on COVID-19 vaccine acceptability among Black individuals in the U.S. has examined the unique experiences of Black immigrants. MethodsBetween January and February 2021, we conducted an online quantitative survey of first and second generation Black immigrants across the U.S. (n = 388). We fit bivariate and multivariable multinomial logistic regression models to examine acceptability of the COVID-19 vaccines. ResultsOverall, 57% of participants reported that they would get the COVID-19 vaccine immediately if it was available to them or had already received at least one dose of the vaccine, 37% would delay getting the vaccine, and 6% indicated that they would never get the vaccine. Compared to participants who reported that they would get the COVID-19 vaccine immediately/had already received at least one dose, participants who indicated that they would never get the vaccine were more likely to have an associate’s degree or lower [adjusted odds ratio (aOR) 9.25; 95% confidence interval (CI): 2.34 to 36.6] and a bachelor’s degree (aOR 3.79; 95% CI: 1.14 to 12.6) compared to having a master’s degree or higher. Additionally, compared to participants who reported that they would get the COVID-19 vaccine immediately/had already received at least one dose, participants who indicated that they would delay getting the COVID-19 vaccine were more likely to: identify as female (aOR 2.62; 95% CI: 1.45 to 4.72), identify as heterosexual (aOR 4.33; 95% CI: 1.46 to 12.9), report having been employed in healthcare operations and care delivery in the previous 6 months (aOR 2.08; 95% CI: 1.02 to 4.25), and history of a laboratory-confirmed COVID-19 diagnosis (aOR 2.44; 95% CI: 1.15 to 5.19). ConclusionOur results suggest that COVID-19 vaccine hesitancy may be high among Black immigrants in the U.S. We found that lower educational attainment, being female, and employment in healthcare setting were associated with vaccine refusal and delay. Culturally-relevant interventions are needed to ensure optimal vaccination rates among this vulnerable population.

Dynamic analysis and application of a dengue transmission model with vaccination and incubation delays

Dynamic analysis and application of a dengue transmission model with vaccination and incubation delays

Factors influencing the acceptability of COVID-19 vaccination: A cross-sectional study from Malaysia

BackgroundWith the surge of COVID-19 cases worldwide, vaccines against COVID-19 are also developing across the countries. However, the acceptability of COVID-19 vaccination among general people is questionable. The availability of several vaccines’ options against COVID-19 has perplexed people regarding individual vaccines’ efficacy and safety. Therefore, we aim to determine the acceptance, preferences, impact factors of future COVID-19 vaccines in Malaysia and the factors influencing the COVID-19 vaccination acceptance among vaccine demand and vaccine delay groups. Material and methodsAn online-based cross-sectional survey was conducted among Malaysian residents 18 years and above of either gender using the snowball sampling technique. A self-administered questionnaire was made available to participants through various social media networks, email, and telegram. The data obtained from the survey were analyzed using SPSS version 25.0. Association between background characteristics and respondents were analyzed using the Chi-square test in the vaccine delay group and vaccine acceptance group. ResultsTotal of 1282 responses were considered for the study, mainly from male respondents (71%). Among the respondents, 95.9% thought that vaccination would be an effective way to prevent and control COVID-19, and 96% would accept vaccination if the COVID-19 vaccine were successfully developed and approved for listing in the future. Essential factors influencing vaccination decisions were vaccine convenience (95.7%) and doctor's recommendation (97.3%). Bivariate analysis revealed that age less than 24 years, Malay race, living in urban areas, tertiary education, students, single marital status, family income (Malaysian ringgits) RM 4,850 to RM 10,959 and >RM 10,960 were significantly associated with vaccine acceptance of COVID19 vaccination. ConclusionAll the factors influencing COVID-19 vaccine acceptance rates throughout the country should be studied on a larger scale, and appropriate steps to ensure vaccine acceptance among the public should be meticulously devised by the government and related authorities.

Classification of Covid-19 vaccine data screening with Naive Bayes algorithm using Knowledge Discovery in database method

Acute Respiratory Syndrome Coronavirus-2 (SARS-Cov-2) known as covid-19 was detected and caused a very large number of deaths due to a mysterious respiratory disease. With the death toll continuing to rise, the government was forced to take swift action to break the chain of spread and reduce the number of deaths by taking vaccinations. An adequate vaccine against Covid-19 is expected to vaccinate at least 70% of the population. Therefore, this study was carried out as a step to help break the chain of the spread of the Covid-19 virus, by classifying the Covid-19 vaccine screening data. The research method applied in this study is the Knowledge Discovery in Database (KDD) method, in which there are several processes, namely selection, pre-processing, transformation, data mining, and evaluation. The application of the Naive Bayes method is expected to be able to classify Covid-19 vaccine screening data with vaccine class values, no, and delay. The results of the research on the classification of the Naive Bayes method show that there are 959 data with Vaccine data 695, No 200, and Delay 64. Processed using the Rapidminer application, the accuracy is 96.56%, Precision is 92.46%, and Recall is 92.13%.

Perbandingan Metode Naïve Bayes dan Support Vector Machine Untuk Analisis Sentimen Terhadap Vaksin Astrazeneca di Twitter

The implementation of Covid-19 vaccination in Indonesia turned out to have various pro and contra opinions from the public. The discovery of disinformation and misinformation about vaccines spread through social media content affects a person's absorption of information so which leads to vaccine delays. When in fact, vaccination is one of the biggest and most effective contributions to preventing the Covid-19 pandemic. Astrazeneca is one of the vaccines provided by the Indonesian government. This vaccine used to be controversial amongst the public regarding its halalness and the safety of the vaccine because of the issue of the said vaccine containing swine trypsin. Nowadays Twitter has become a place for users to express their concerns and opinion regarding the Covid-19 vaccine. Data obtained from Twitter will be useful if it is analyzed, one of which is sentiment analysis. In this study, data collection was carried out using the snscrape library with a total of 3105 tweets obtained from the period May to June 31, 2021. The dataset that has been collected is then preprocessed to optimize the data. After passing the preprocessing stage, the data was labeled as tweet class using a lexicon-based dictionary which resulted in 1275 tweets with positive opinin labels and 1830 tweets labeled as negative opinion. The aim of this study is to examines the performance of Naïve Bayes and Support Vector Machine with adding the weighting method TF-IDF (Term Frequency – Inverse Document Frequency). The evaluation results show that the Support Vector Machine has a greater accuracy, precision, recall and f1-score of 87.27%, 90.41%, 77,34% and 83.37% compared to Naïve Bayes which has an accuracy, precision, recall and f1- of 76.81%, 72.40%, 70.70% and 71.52%.

Childhood Immunization Coverage at a Tertiary Care Centre in South India Pre and Post COVID Lockdown - A Retrospective Study

Introduction: Childhood immunisation is the most cost effective method to prevent vaccine preventable diseases and decrease childhood morbidity and mortality. COVID-19 pandemic has affected routine immunisation of children due to various reasons. We aimed to study the attendance to immunisation clinic at our tertiary care hospital prior and during COVID-19 pandemic.&#x0D; Methods: Retrospective data of monthly attendance to the immunisation clinic at our tertiary care hospital was collected for a study period of 30months, sub-grouped into - January 2019 to March 2020 (pre-COVID) and April 2020 to June 2021 (during COVID). The clinic caters to children from first day of life till 18 years, as per National Immunisation Schedule (NIS). Trends in attendance across the months were studied. Statistical analysis were employed to test whether there was a significant reduction in immunisation clinic attendance.&#x0D; Results: Attendance to the immunisation clinic during the 30 month study period was 37418 children. Among these, 29879 children received birth dose vaccines. This cohort was excluded from further analysis as deliveries continued at our maternity centre in both periods of study. Comparing vaccine recipients above the age of 6weeks till 18years across the months, 6222 and 1502 children received immunisation in the pre-COVID and during COVID pandemic respectively. No child received immunisation from April 2020 to July 2020 during national lockdown. Unpaired t-test showed highly significant reduction in attendance to immunisation clinic during the COVID pandemic in comparison to pre-COVID period (p&lt;0.001). The reduction in immunisation attendance had greatest affection among recipients of pentavalent vaccine at our centre.&#x0D; Conclusion: Immunisation among children is significantly hampered during this COVID-19 pandemic as highlighted by our study findings. Vaccination delay leaves young children vulnerable and there is an acute need to increase awareness and catch-up drives to prevent resurgence of vaccine preventable diseases.

COVID-19 Vaccine Acceptance and Its Determinants in the General Population of Delhi, India: A State Level Cross-Sectional Survey.

Objective: To ascertain the COVID-19 vaccination acceptance and the factors contributing to vaccine hesitancy and vaccine confidence in the adult population, and the intention for vaccination of their children.Methods: This cross-sectional analysis reports the ancillary results of a population-based SARS-CoV-2 serosurvey conducted in Delhi, India, from September 24 to October 14, 2021. Data were collected from 20312 adult participants through a multistage sampling method from all the 274 wards in the 11 districts of the national capital territory region.Results: We enrolled 12093 (59.3%) females and 8219 (40.5%) male participants with mean (SD) age of 40.3 (14.6) years. The vaccine acceptance rate in the participants was 67.7% (95% CI 67.1, 68.4), with 6031 (43.8%) having received one dose and 7727 (56.2%) having received two vaccine doses. On adjusted analysis, lack of vaccine acceptance was independently associated with female gender aOR 1.15 (95% CI 1.1, 1.23), younger age-group (18-49 years) aOR 1.85 (95% CI 1.71, 2.0), low educational status aOR 1.88 (95% CI 1.77, 2.0), in those with no history of COVID-19 aOR 1.81 (95% CI 1.69, 1.95), non-healthcare workers aOR 2.1 (95% CI 1.7, 2.53), and in the absence of hypertension comorbidity aOR 1.22 (1.1, 1.38). Lack of awareness of COVID-19 vaccines, including doubts on vaccine efficacy and long-term safety, were primary drivers of vaccine hesitancy in the unvaccinated subgroup. Only 35.6% participants reported a positive intention to vaccinate their children.Conclusions: One in three adults lacked vaccine acceptance. High prevalence of delay in second dose vaccination was also observed.

Incorporating Fuzzy Cognitive Inference for Vaccine Hesitancy Measuring

Vaccine hesitancy plays a key role in vaccine delay and refusal, but its measurement is still a challenge due to multiple intricacies and uncertainties in factors. This paper attempts to tackle this problem through fuzzy cognitive inference techniques. Firstly, we formulate a vaccine hesitancy determinants matrix containing multi-level factors. Relations between factors are formulated through group decision-making of domain experts, which results in a fuzzy cognitive map. The subjective uncertainty of linguistic variables is expressed by fuzzy numbers. A double-weighted method is designed to integrate the distinguished decisions, in which the subjective hesitancy is considered for each decision. Next, three typical scenarios are constructed to identify key and sensitive factors under different experimental conditions. The experimental results are further discussed, which enrich the approaches of vaccine hesitancy estimation for the post-pandemic global recovery.

The impact of COVID-19 Pandemic on Routine Childhood Immunization in Baghdad/Al-Karkh

Background: The coronavirus disease 2019 (COVID-19) pandemic is extensively impacting national and international public health. Routine childhood immunization is projected for being adversely affected by COVID-19 mitigation measures. Consequently, vaccine preventable disease outbreak might be a big problem to encounter in the near future. Objectives: The aim of the study is to evaluate the prevalence of vaccination delay and explore the barriers leading to that and parents' attitude toward the importance of vaccination timelines. Materials and Methods: A cross-sectional study was carried out during the period between of May 1st and of August 1st, 2021. A sample of 400 parents attending vaccination unit with their under 2-year-old children were selected from health-care centers from Al-Karkh directorate. Results: The study shows that 266 (66.5%) of the parents were mothers, 134 (33.5%) were fathers, 288 (72%) of them were aged 30 y ears or less, 210 (52.5%) of them were college graduate or higher educational level, 302 (75.5%) of them did not have a health worker in their family, 292 (73%) of them had &lt;3 children. This study revealed that 274 (68.5%) of the parents reported a delay in their children's vaccination timeliness, 198 (49.5%) of which was significant delay of more than 1 month and 76 (19%) was a delay of 2–4 weeks only. 126 (31.5%) reported an on-time vaccination. This study also showed a highly significant association between vaccination delay and history of COVID-19 infection in the family. This study demonstrated that curfew and difficulty in transportation 154 (38.5%) and fear of getting COVID-19 infection 142 (35.5%) were the most encountered barriers for vaccination delay. This study also showed that 51% of the parents had good level of attitude toward the importance of vaccination timeliness for their children. In addition, it showed a significant association between the level of attitude with the age and educational level of the parents and with having a health worker in the family. Conclusion: We conclude that 68.5% of sample had vaccination delay since the COVID-19 pandemic has started and good level of attitude toward the importance of vaccination timeliness. This indicates the need for strict recommendation about the importance of routine immunization schedule and need to commit to it even during pandemic situations.

We should abandon the Brighton Collaboration criteria for vaccine-associated anaphylaxis

We should abandon the Brighton Collaboration criteria for vaccine-associated anaphylaxis

Severe pertussis disease in a paediatric population: The role of age, vaccination status and prematurity.

To estimate hospitalisation rate and investigate the role of age, prematurity and vaccination status in severe pertussis cases. We retrospectively evaluated 200 children aged 0-14 years, admitted to the emergency rooms of Meyer Hospital of Florence and Pisa Hospital with a diagnosis of pertussis from 1 October 2010 to 31 January 2020. Children younger than 12months were 63.0%. Preterm infants were 6.5%. The rate of hospitalisation was 49.0%. Among hospitalised cases, 80.6% were younger than 5 months. Overall, 62.0% were unvaccinated; this percentage increased among hospitalised (73.5%) and preterm subsamples (76.9%). Delays in pertussis vaccination were found in 57.7% of term infants and in 80.0% of preterms. Multivariable analysis confirmed the age under 2 months as the variable at higher risk for hospitalisation (OR 4.49, 95% CI 1.85-10.96, p< 0.001). Being fully vaccinated represented a significant protective factor (OR 0.12, 95% CI 0.04-0.35, p< 0.001). Older classes of age and a complete vaccination, in time with the recommended schedule, are both protective factors for hospitalisation in severe pertussis disease. The widespread vaccination delay frequently observed in preterm children may be the cause for their higher rate of hospitalisation.

Delayed vaccination the children up to 2years of age.

To analyze factors associated with vaccination delay in children up to 2years of age. Cross-sectional study with primary data from a probabilistic sample of 388 children born in 2015. The data were described using absolute and relative frequencies. For the analysis of factors associated with vaccination delay, Cox proportional risk regression was performed, considering the time from birth to the first vaccination delay as a dependent variable and as sociodemographic, economic, behavioral aspects related to health services as independent variables. The delayed vaccination rate was 88.66%. Variables associated with delayed vaccination were: mother's health problems during delivery or in the first 7days (HR: 0.68; 95% CI: 0.48-0.96); hospitalization of the child in the first 2years of life (HR: 1.52; 95% CI: 1.10-2.11); mother's poor bond with health professionals at the health unit (HR: 1.75; 95% CI: 1.01-3.03); purposeful decision to delay or not to vaccinate the child (HR: 1.56; 95% CI: 1.14-2.13). The factors associated with health care, such as the mother's health problems, the child's hospitalization in the first 2years of life, and the bond between the mother and the health professionals affect the timeliness of vaccine doses.

HPV vaccine delay and refusal among unvaccinated Mexican American young adult women: a qualitative investigation of Mexican-born and US-born HPV vaccine decision narratives.

Low HPV vaccination rates among Latina young adults perpetuate HPV-associated cancer disparities. Using qualitative methods, this study explored individual, interpersonal, and community factors that influence HPV vaccine delay and refusal among Mexican- and U.S.-born Mexican American young adult women. Participants (N = 30) between 18 and 26 years old were purposively sampled from two federally qualified health centers in Orange County, California. The National Institute on Minority Health and Health Disparities research framework and narrative engagement theory guided semi-structured phone interviews coded inductively and deductively. Participants primarily attributed vaccine status to individual and interpersonal reasons. Emerging themes included low HPV vaccine knowledge, insufficient provider communication, negative perceptions about HPV and the vaccine, motherhood responsibilities, mother’s communication about HPV, cultural family norms, health care access, and misinformation. Compared to U.S.-born Latinas, Mexican-born participants more frequently expressed avoiding health care discussions with family. HPV vaccine recommendations for young Mexican American women should include socioculturally tailored messages that may improve HPV vaccination acceptance and uptake.

Invited Commentary: The Use of Population Attributable Fractions in Studies of Vaccine Hesitancy.

Vaccine hesitancy-the delay or refusal of vaccines despite their availability-has been linked to lower vaccination rates and outbreaks of vaccine-preventable diseases. Using cross-sectional surveys of 78,725 parents and other family members in the United States, Nguyen et al. (Am J Epidemiol. 2022;191(9):1626-1635) calculated the population attributable fraction (PAF) of vaccine hesitancy on nonreceipt of recommended childhood vaccines, including influenza vaccine. The PAF is readily calculated: p(rr - 1)/rr, where p is the proportion of those hesitant among nonvaccinated individuals, and rr is the risk ratio of nonvaccination between those hesitant over those nonhesitant. By vaccine, the PAF ranged from 6.5% for nonreceipt of the hepatitis B vaccine birth dose to 31.3% for nonreceipt of the diphtheria-tetanus-pertussis vaccine dose 3. For nonreceipt of influenza vaccine, the PAF varied geographically, with relatively high values in some Northeast (e.g., New York at 22.6%) and Northwest (e.g., Oregon at 23.0%) states and lower values in certain Southern (e.g., Louisiana at 7.5%) and Mountain West (e.g., Utah at 8.8%) states. The PAF can elucidate the contribution of vaccine hesitancy on nonvaccination in different circumstances. Future studies can apply this technique in different populations and incorporate different measures of vaccine hesitancy.