scholarly journals Comparative effectiveness of allocation strategies of COVID-19 vaccines and antivirals against emerging SARS-CoV-2 variants of concern in East Asia and Pacific region

2021 ◽  
Author(s):  
Kathy Leung ◽  
Mark Jit ◽  
Gabriel M Leung ◽  
Joseph T Wu
Keyword(s):  
East Asia ◽  
Vaccination Coverage ◽  
Vaccine Coverage ◽  
Primary Vaccination ◽  
Vaccine Uptake ◽  
Transmission Model ◽  
Pacific Region ◽  
Additional Dose ◽  
The Impact ◽  
Allocation Strategies

Background We aimed to evaluate the impact of various allocation strategies of COVID-19 vaccines and antiviral such that the pandemic exit strategy could be tailored to risks and preferences of jurisdictions in the East Asia and Pacific region (EAP) to improve its efficiency and effectiveness. Methods Vaccine efficacies were estimated from the titre distributions of 50% plaque reduction neutralization test (PRNT50), assuming that PRNT50 titres of primary vaccination decreased by 2-10 folds due to antibody waning and emergence of VOCs, and an additional dose of vaccine would increase PRNT50 titres by 3- or 9-fold. We then used an existing SARS-CoV-2 transmission model to assess the outcomes of vaccine allocation strategies with and without the use of antivirals for symptomatic patients in Japan, Hong Kong and Vietnam. Findings Increasing primary vaccination coverage was the most important contributing factor in reducing the total and peak number of COVID-19 hospitalizations, especially when population vaccine coverage or vaccine uptake among older adults was low. Providing antivirals to 50% of symptomatic infections only further reduced total and peak hospitalizations by 10-13%. The effectiveness of an additional dose of vaccine was highly dependent on the immune escape potential of VOCs and antibody waning, but less dependent on the boosting efficacy of the additional dose. Interpretation Increasing primary vaccination coverage should be prioritised in the design of allocation strategies of COVID-19 vaccines and antivirals in the EAP region. Heterologous vaccination with any available vaccine as the additional dose could be considered when planning pandemic exit strategies tailored to the circumstances of EAP jurisdictions.

scholarly journals The importance of sustained compliance with physical distancing during COVID-19 vaccination rollout

2021 ◽  
Author(s):  
Alexandra Teslya ◽  
Ganna Rozhnova ◽  
Thi Mui Pham ◽  
Daphne van Wees ◽  
Hendrik Nunner ◽  
...  
Keyword(s):  
Vaccination Coverage ◽  
Vaccine Coverage ◽  
Transmission Model ◽  
Cumulative Number ◽  
Vaccination Rates ◽  
Contact Rates ◽  
Health Authorities ◽  
Public Health Authorities ◽  
Vaccination Campaigns ◽  
The Impact

Abstract Mass vaccination campaigns against SARS-CoV-2 are under way in many countries with the hope that increasing vaccination coverage will enable reducing current physical distancing measures. Compliance with these measures is waning, while more transmissible virus variants such as B.1.1.7 have emerged. Using SARS-CoV-2 transmission model we investigated the impact of the feedback between compliance, the incidence of infection, and vaccination coverage on the success of a vaccination programme in the population where waning of compliance depends on vaccine coverage. Our results suggest that the combination of fast waning compliance, slow vaccination rates, and more transmissible variants may result in a higher cumulative number of infections than in a situation without vaccination. These adverse effects can be alleviated if vaccinated individuals do not revert to pre-pandemic contact rates, and if non-vaccinated individuals remain compliant with physical distancing measures. Both require convincing, clear and appropriately targeted communication strategies by public health authorities.

scholarly journals The importance of sustained compliance with physical distancing during COVID-19 vaccination rollout

2021 ◽  
Author(s):  
Alexandra Teslya ◽  
Ganna Rozhnova ◽  
Thi Mui Pham ◽  
Daphne A van Wees ◽  
Hendrik Nunner ◽  
...  
Keyword(s):  
Public Health ◽  
Vaccination Coverage ◽  
Vaccine Coverage ◽  
Vaccine Uptake ◽  
Transmission Model ◽  
Cumulative Number ◽  
Contact Rates ◽  
Health Authorities ◽  
Public Health Authorities ◽  
Vaccination Campaigns

Mass vaccination campaigns against SARS-CoV-2 are ongoing in many countries with increasing vaccination coverage enabling relaxation of lockdowns. Vaccination rollout is frequently supplemented with advisory from public health authorities for continuation of physical distancing measures. Compliance with these measures is waning while more transmissible virus variants such as Alpha (B.1.1.7) and Delta (B.1.617.2) have emerged. In this work, we considered a population where the waning of compliance depends on vaccine coverage. We used a SARS-CoV-2 transmission model which captures the feedback between compliance, infection incidence, and vaccination coverage to investigate factors that contribute to the increase of the prevalence of infection during the initial stages of the vaccination rollout as compared to no vaccination scenario. We analysed how the vaccine uptake rate affects cumulative numbers of new infections three and six months after the start of vaccination. Our results suggest that the combination of fast waning compliance in non-vaccinated population, low compliance in vaccinated population and more transmissible virus variants may result in a higher cumulative number of new infections than in a situation without vaccination. These adverse effects can be alleviated if vaccinated individuals do not revert to pre-pandemic contact rates, and if non-vaccinated individuals remain compliant with physical distancing measures. Both require convincing, clear and appropriately targeted communication strategies by public health authorities.

scholarly journals The importance of sustained compliance with physical distancing during COVID-19 vaccination rollout

2021 ◽  
Author(s):  
Alexandra Teslya ◽  
Ganna Rozhnova ◽  
Thi Mui Pham ◽  
Daphne van Wees ◽  
Hendrik Nunner ◽  
...  
Keyword(s):  
Vaccination Coverage ◽  
Vaccine Coverage ◽  
Transmission Model ◽  
Cumulative Number ◽  
Vaccination Rates ◽  
Contact Rates ◽  
Health Authorities ◽  
Public Health Authorities ◽  
Vaccination Campaigns ◽  
The Impact

Abstract Mass vaccination campaigns against SARS-CoV-2 are under way in many countries with the hope that increasing vaccination coverage will enable reducing current physical distancing measures. Compliance with these measures is waning, while more transmissible virus variants such as B.1.1.7 have emerged. Using SARS-CoV-2 transmission model we investigated the impact of the feedback between compliance, the incidence of infection, and vaccination coverage on the success of a vaccination programme in the population where waning of compliance depends on vaccine coverage. Our results suggest that the combination of fast waning compliance, slow vaccination rates, and more transmissible variants may result in a higher cumulative number of infections than in a situation without vaccination. These adverse effects can be alleviated if vaccinated individuals do not revert to pre-pandemic contact rates, and if non-vaccinated individuals remain compliant with physical distancing measures. Both require convincing, clear and appropriately targeted communication strategies by public health authorities.

Influenza vaccination coverage in a population-based cohort of Australian-born Aboriginal and non-Indigenous older adults

2019 ◽  
Vol 43 ◽  
Author(s):  
Amalie Dyda ◽  
Surendra Karki ◽  
Marlene Kong ◽  
Heather F Gidding ◽  
John M Kaldor ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Vaccination Coverage ◽  
Torres Strait Islander ◽  
Vaccine Coverage ◽  
Vaccine Uptake ◽  
P Value ◽  
Healthy Weight ◽  
Medical Risk ◽  
Torres Strait

Background: There is limited information on vaccination coverage and characteristics associated with vaccine uptake in Aboriginal and/or Torres Strait Islander adults. We aimed to provide more current estimates of influenza vaccination coverage in Aboriginal adults. Methods: Self-reported vaccination status (n=559 Aboriginal and/or Torres Strait Islander participants, n=80,655 non-Indigenous participants) from the 45 and Up Study, a large cohort of adults aged 45 years or older, was used to compare influenza vaccination coverage in Aboriginal and/or Torres Strait Islander adults with coverage in non-Indigenous adults. Results: Of Aboriginal and non-Indigenous respondents aged 49 to <65 years, age-standardised influenza coverage was respectively 45.2% (95% CI 39.5–50.9%) and 38.5%, (37.9–39.0%), p-value for heterogeneity=0.02. Coverage for Aboriginal and non-Indigenous respondents aged ≥65 years was respectively 67.3% (59.9–74.7%) and 72.6% (72.2–73.0%), p-heterogeneity=0.16. Among Aboriginal adults, coverage was higher in obese than in healthy weight participants (adjusted odds ratio (aOR)=2.38, 95%CI 1.44–3.94); in those aged <65 years with a medical risk factor than in those without medical risk factors (aOR=2.13, 1.37–3.30); and in those who rated their health as fair/poor compared to those who rated it excellent (aOR=2.57, 1.26–5.20). Similar associations were found among non-Indigenous adults. Conclusions: In this sample of adults ≥65 years, self-reported influenza vaccine coverage was not significantly different between Aboriginal and non-Indigenous adults whereas in those <65 years, coverage was higher among Aboriginal adults. Overall, coverage in the whole cohort was suboptimal. If these findings are replicated in other samples and in the Australian Immunisation Register, it suggests that measures to improve uptake, such as communication about the importance of influenza vaccine and more effective reminder systems, are needed among adults.

Vaccine Coverage Across the Life Course in Michigan During the COVID-19 Pandemic: January–September 2020

2021 ◽  
pp. e1-e9
Author(s):  
Angela K. Shen ◽  
Cristi A. Bramer ◽  
Lynsey M. Kimmins ◽  
Robert Swanson ◽  
Patricia Vranesich ◽  
...  
Keyword(s):  
Life Course ◽  
Vaccination Coverage ◽  
Vaccine Coverage ◽  
Childhood Vaccination ◽  
Local Health ◽  
Immunization Registry ◽  
Immunization Services ◽  
Vaccines For Children ◽  
The Life Course ◽  
The Impact

Objectives. To assess the impact of the COVID-19 pandemic on immunization services across the life course. Methods. In this retrospective study, we used Michigan immunization registry data from 2018 through September 2020 to assess the number of vaccine doses administered, number of sites providing immunization services to the Vaccines for Children population, provider location types that administer adult vaccines, and vaccination coverage for children. Results. Of 12 004 384 individual vaccine doses assessed, 48.6%, 15.6%, and 35.8% were administered to children (aged 0–8 years), adolescents (aged 9–18 years), and adults (aged 19–105 years), respectively. Doses administered overall decreased beginning in February 2020, with peak declines observed in April 2020 (63.3%). Overall decreases in adult doses were observed in all settings except obstetrics and gynecology provider offices and pharmacies. Local health departments reported a 66.4% decrease in doses reported. For children, the total number of sites administering pediatric vaccines decreased while childhood vaccination coverage decreased 4.4% overall and 5.8% in Medicaid-enrolled children. Conclusions. The critical challenge is to return to prepandemic levels of vaccine doses administered as well as to catch up individuals for vaccinations missed. (Am J Public Health. Published online ahead of print October 7, 2021: e1–e9. https://doi.org/10.2105/AJPH.2021.306474 )

scholarly journals Identifying silent COVID-19 infections among children is critical for controlling the pandemic

2021 ◽  
Author(s):  
Seyed M. Moghadas ◽  
Meagan C. Fitzpatrick ◽  
Affan Shoukat ◽  
Kevin Zhang ◽  
Alison P. Galvani
Keyword(s):  
Vaccination Coverage ◽  
Vaccine Efficacy ◽  
The United States ◽  
Sensitivity Analyses ◽  
Transmission Model ◽  
Base Case ◽  
Age Group ◽  
One Year ◽  
The Impact ◽  
Targeted Approach

Importance: A significant proportion of COVID-19 transmission occurs silently during the pre-symptomatic and asymptomatic stages of infection. Children, while being important drivers of silent transmission, are not included in COVID-19 vaccination campaigns given their exclusion from clinical trials thus far. Objective: To investigate the impact of a targeted approach to identifying silent infections among children as a proxy for their vaccination. Design: This study used an age-structured disease transmission model to simulate the synergistic impact of interventions in reducing attack rates over the course of one year. Setting: A synthetic population representative of the demographics of the United States (US). Participants: Six age groups of 0-4, 5-10, 11-18, 19-49, 50-64, 65+ years old, stratified for their population size based on US census data. Exposures: Vaccination of adults, self-isolation of all symptomatic cases within 24 hours of symptom onset, and detection of silent infections. Main Outcomes and Measures: Vaccination of adults was implemented to reach a 40% coverage over the course of one year with a vaccine efficacy of 95% against symptomatic and severe COVID-19. Without vaccination of children, we determined the proportion and speed that would be required for identifying silent infections among this age group to suppress future attack rates below 5%. Results: A targeted approach that identifies 20.6% and 28.6% of silent infections among children within 2 or 3 days post-infection, respectively, would be required to bring attack rates under 5% with vaccination of adults. If silent infections among children remained undetected, achieving the same attack rates would require an unrealistically high vaccination coverage (at least 82%) of this age group, in addition to the base-case 40% vaccination coverage of adults. The results were robust in sensitivity analyses with respect to vaccine efficacy against infection and reduced susceptibility of children to infection. Conclusions and Relevance: In the absence of vaccine availability for children, a targeted approach to rapid identification of silent COVID-19 infections in this age group can significantly mitigate disease burden. Without measures to interrupt transmission chains from silent infections, vaccination of adults is unlikely to contain the outbreaks in the near term.

scholarly journals 1238Estimating the non-specific effects of seasonal influenza vaccine on RSV-hospitalisations in children

2021 ◽  
Vol 50 (Supplement_1) ◽  
Author(s):  
Huong Le ◽  
Christopher Blyth ◽  
Heather Gidding ◽  
Tom Snelling ◽  
Parveen Fathima ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Seasonal Influenza ◽  
Vaccine Coverage ◽  
Population Based ◽  
Vaccine Uptake ◽  
Respiratory Pathogens ◽  
Seasonal Influenza Vaccine ◽  
Specific Effects ◽  
Syncytial Virus ◽  
The Impact

Abstract Background Seasonal influenza vaccine is effective against influenza hospitalisations, but little is known about non-specific effects on other respiratory pathogens with similar seasonal patterns. We aimed to assess the causal impact of seasonal influenza vaccine on laboratory-confirmed hospitalisations for respiratory syncytial virus (RSV) in children using an instrumental variable (IV) strategy. Methods We used population-based probabilistically linked data on births, childhood immunisations, deaths, hospitalisations, perinatal and statewide microbiology data (2000-2013) in Western Australia (WA). Our analysis cohort included children up to age 7 years. We exploited WA’s unique preschool influenza vaccination policy commencing in 2008 and used this as an instrument for vaccination status. We estimated a system of two simultaneous probit equations: determinants of influenza vaccine uptake, and determinants of RSV-confirmed hospitalisation. Results Influenza vaccine coverage was low prior to 2008 but increased to 33.7% in children aged 6-23 months in 2009. RSV-hospitalisations ranged from 3.5/1000 children (12-23 months) to 6.4/1000 (6-12 months). Receipt of seasonal influenza vaccine reduced RSV-hospitalisations in the population cohort of children aged &lt;2 years by an average of 0.21% in the same year (p &lt; 0.001). Conclusions To our knowledge, this is the first analysis utilising an IV estimation strategy to assess the impact of influenza vaccine on RSV-hospitalisations. We estimated a small, but highly statistically significant impact that warrants further investigation using contemporary data. Key messages RSV is a leading cause of childhood morbidity. The role of influenza vaccine offering cross protection to RSV could be further explored prior to RSV vaccines being commercially available.

scholarly journals The impact of local vaccine coverage and recent incidence on measles transmission in France between 2009 and 2018

2021 ◽  
Author(s):  
Alexis Robert ◽  
Adam J Kucharski ◽  
Sebastian Funk
Keyword(s):  
Vaccine Coverage ◽  
Fold Increase ◽  
Vaccine Uptake ◽  
World Health ◽  
Local Immunity ◽  
Routine Immunisation ◽  
Population Movements ◽  
Local Risk ◽  
The Impact ◽  
Local Transmission

Background Despite high levels of vaccine coverage, sub-national heterogeneity in immunity to measles can create pockets of susceptibility, which are hard to detect and may result in long-lasting outbreaks. The elimination status defined by the World Health Organization aims to identify countries where the virus is no longer circulating and can be verified after 36 months of interrupted transmission. However, since 2018, numerous countries have lost their elimination status soon after reaching it, showing that the indicators used to define elimination may not be predictive of lower risks of outbreaks. Methods and Findings We quantified the impact of local vaccine coverage and recent levels of incidence on the dynamics of measles in each French department between 2009 and 2018, using mathematical models based on the 'Epidemic-Endemic' regression framework. High values of local vaccine coverage were associated with fewer imported cases and lower risks of local transmissions. Regions that had recently reported high levels of incidence were also at a lower risk of local transmission, potentially due to additional immunity accumulated during these recent outbreaks. Therefore, all else being equal, the risk of local transmission was not lower in areas fulfilling the elimination criteria (i.e., low recent incidence). After fitting the models using daily case counts, we used the parameters' estimates to simulate the effect of variations in the vaccine coverage and recent incidence on future transmission. A decrease of 3% in the three-year average vaccine uptake led to a five-fold increase in the number of cases simulated in a year on average. Conclusions Spatiotemporal variation in vaccine coverage because of disruption of routine immunisation programmes, or lower trust in vaccines, can lead to large increases in both local and cross regional transmission. The association found between local vaccine coverage and incidence suggests that, although regional vaccine uptake can be hard to collect and unreliable because of population movements, it can provide insights into the risks of imminent outbreak. Periods of low local measles incidence were not indicative of a decrease in the risks of local transmission. Therefore, the incidence indicator used to define the elimination status was not consistently associated with lower risks of measles outbreak in France. More detailed models of local immunity levels or subnational seroprevalence studies may yield better estimates of local risk of measles outbreaks.

scholarly journals An Internet-Based Survey of Influenza Vaccination Coverage in Healthcare Workers in China, 2018/2019 Season

Vaccines ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 6 ◽  
Author(s):  
Haitao Liu ◽  
Yayun Tan ◽  
Muli Zhang ◽  
Zhibin Peng ◽  
Jiandong Zheng ◽  
...  
Keyword(s):  
Influenza Vaccine ◽  
Influenza Vaccination ◽  
Vaccination Coverage ◽  
Healthcare Workers ◽  
Online Survey ◽  
Vaccine Coverage ◽  
National Level ◽  
Influence Factors ◽  
Multivariate Logistic Regression Analysis ◽  
Vaccine Uptake

Influenza vaccination coverage was low among healthcare workers (HCWs) in China. In October 2018, the National Health Commission of China began to require all hospitals to provide free influenza vaccination for HCWs to increase vaccine uptake, and no study on vaccine coverage among HCWs at the national level after the announcement of new policy. This evaluation aims to investigate self-reported influenza vaccination coverage among HCWs and factors that may affect vaccine receipt during the 2018/2019 influenza season. We delivered an opt-in internet panel survey among registered HCWs of DXY forum (the biggest online forum for HCWs in China). The survey was self-administered using a standard questionnaire to collect information on demographics, occupational characteristics, policy implementation, influenza vaccination and influence factors. We conducted multivariate logistic regression analysis to assess factors associated with receipt of influenza vaccine. The response rate of this online survey was 3.6%. The seasonal influenza vaccine coverage reported among HCWs surveyed during the 2018/2019 season was 11.6% (472/4078). Only 19.0% (774/4078) of HCWs surveyed reported free policy in their workplace. Combing free policy and workplace requirement proved to be effective to improve influenza vaccination coverage in HCWs (PR = 6.90, 95% CI: 6.03–7.65). The influenza vaccination coverage among surveyed HCWs in China was low during the 2018/2019 season. To increase future vaccination uptake, we recommend a multi-faceted strategy that include free policy, workplace requirement and promotion, on-site vaccination, and monitoring.

scholarly journals Impact of vaccination and birth rate on the epidemiology of pertussis: a comparative study in 64 countries

2010 ◽  
Vol 277 (1698) ◽  
pp. 3239-3245 ◽  
Author(s):  
H. Broutin ◽  
C. Viboud ◽  
B. T. Grenfell ◽  
M. A. Miller ◽  
P. Rohani
Keyword(s):  
Birth Rate ◽  
Vaccine Coverage ◽  
Strong Association ◽  
Herd Immunity ◽  
Public Health Problem ◽  
Recruitment Rate ◽  
Vaccine Uptake ◽  
Important Public Health Problem ◽  
Epidemic Period ◽  
The Impact

Bordetella pertussis infection remains an important public health problem worldwide despite decades of routine vaccination. A key indicator of the impact of vaccination programmes is the inter-epidemic period, which is expected to increase with vaccine uptake if there is significant herd immunity. Based on empirical data from 64 countries across the five continents over the past 30–70 years, we document the observed relationship between the average inter-epidemic period, birth rate and vaccine coverage. We then use a mathematical model to explore the range of scenarios for duration of immunity and transmission resulting from repeat infections that are consistent with empirical evidence. Estimates of pertussis periodicity ranged between 2 and 4.6 years, with a strong association with susceptible recruitment rate, defined as birth rate × (1 − vaccine coverage). Periodicity increased by 1.27 years on average after the introduction of national vaccination programmes (95% CI: 1.13, 1.41 years), indicative of increased herd immunity. Mathematical models suggest that the observed patterns of pertussis periodicity are equally consistent with loss of immunity that is not as rapid as currently thought, or with negligible transmission generated by repeat infections. We conclude that both vaccine coverage and birth rate drive pertussis periodicity globally and that vaccination induces strong herd immunity effects. A better understanding of the role of repeat infections in pertussis transmission is critical to refine existing control strategies.

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