scholarly journals Predicting the impact of measles vaccination in England and Wales: model validation and analysis of policy options

1995 ◽  
Vol 114 (2) ◽  
pp. 319-344 ◽  
Author(s):  
H. R. Babad ◽  
D. J. Nokes ◽  
N. J. Gay ◽  
E. Miller ◽  
P. Morgan-Capner ◽  
...  
Keyword(s):  
Vaccine Coverage ◽  
Case Reports ◽  
Vaccination Campaign ◽  
Herd Immunity ◽  
Vaccination Strategy ◽  
School Age Children ◽  
Policy Options ◽  
England And Wales ◽  
Measles Vaccination ◽  
The Impact

SummaryMeasles incidence in England and Wales has fallen to an all-time low. Attention is now focused on preventing local outbreaks, and, in the long run, on the elimination of indigenous measles. A realistic age-structured (RAS) mathematical model of measles transmission is used to reconstruct the impact of measles vaccination in England and Wales from 1968 to the present and to evaluate the merits of future policy options. In general, the predictions of the model show good agreement with long-term age stratified case reports and seroprevalence surveys. The model underestimates the proportion of cases that are notified in 0–2-year-old children. However, recent work suggests a high degree of misdiagnosis in this age group. Projections on the basis of the existing vaccination strategy in the UK suggest that the present level of measles vaccine coverage will be insufficient to eliminate small seasonal outbreaks of measles. This result is, however, sensitive to the assumed level of vaccine efficacy. Explorations of a variety of changes to current vaccination strategy favour a 2-dose schedule with the second dose administered at age 4 years irrespective of vaccination history. A vaccination campaign in school-age children, to reduce deficits in herd immunity, would accelerate progress towards measles elimination.

scholarly journals COVID-19 Vaccine Intention among Healthcare Workers in Saudi Arabia: A Cross-Sectional Survey

Vaccines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 835
Author(s):  
Mohammed Noushad ◽  
Mohammad Zakaria Nassani ◽  
Anas B. Alsalhani ◽  
Pradeep Koppolu ◽  
Fayez Hussain Niazi ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Healthcare System ◽  
Healthcare Workers ◽  
Vaccine Coverage ◽  
Vaccination Campaign ◽  
Herd Immunity ◽  
Positive Sign ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Public Health Strategies

The COVID-19 pandemic has caused largescale morbidity and mortality and a tremendous burden on the healthcare system. Healthcare workers (HCWs) require adequate protection to avoid onward transmission and minimize burden on the healthcare system. Moreover, HCWs can also influence the general public into accepting the COVID-19 vaccine. Therefore, determining COVID-19 vaccine intention among HCWs is of paramount importance to plan tailor-made public health strategies to maximize vaccine coverage. A structured questionnaire was administered in February and March 2021 among HCWs in Saudi Arabia using convenience sampling, proceeding the launch of the vaccination campaign. HCWs from all administrative regions of Saudi Arabia were included in the study. In total, 674 out of 1124 HCWs responded and completed the survey (response rate 59.9%). About 65 percent of the HCWs intended to get vaccinated. The intention to vaccinate was significantly higher among HCWs 50 years of age or older, Saudi nationals and those who followed the updates about COVID-19 vaccines (p < 0.05). The high percentage (26 percent) of those who were undecided in getting vaccinated is a positive sign. As the vaccination campaign gathers pace, the attitude is expected to change over time. Emphasis should be on planning healthcare strategies to convince the undecided HCWs into accepting the vaccine in order to achieve the coverage required to achieve herd immunity.

scholarly journals Impact of national influenza vaccination strategy in severe influenza outcomes among the high-risk Portuguese population

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Ausenda Machado ◽  
Irina Kislaya ◽  
Amparo Larrauri ◽  
Carlos Matias Dias ◽  
Baltazar Nunes
Keyword(s):  
High Risk ◽  
Influenza Vaccination ◽  
Seasonal Influenza ◽  
Vaccine Coverage ◽  
Vaccination Strategy ◽  
High Risk Population ◽  
Risk Population ◽  
Seasonal Influenza Vaccination ◽  
Severe Influenza ◽  
The Impact

Abstract Background All aged individuals with a chronic condition and those with 65 and more years are at increased risk of severe influenza post-infection complications. There is limited research on cases averted by the yearly vaccination programs in high-risk individuals. The objective was to estimate the impact of trivalent seasonal influenza vaccination on averted hospitalizations and death among the high-risk population in Portugal. Methods The impact of trivalent seasonal influenza vaccination was estimated using vaccine coverage, vaccine effectiveness and the number of influenza-related hospitalizations and deaths. The number of averted events (NAE), prevented fraction (PF) and number needed to vaccinate (NVN) were estimated for seasons 2014/15 to 2016/17. Results The vaccination strategy averted on average approximately 1833 hospitalizations and 383 deaths per season. Highest NAE was observed in the ≥65 years population (85% of hospitalizations and 95% deaths) and in the 2016/17 season (1957 hospitalizations and 439 deaths). On average, seasonal vaccination prevented 21% of hospitalizations in the population aged 65 and more, and 18.5% in the population with chronic conditions. The vaccination also prevented 29% and 19.5% of deaths in each group of the high-risk population. It would be needed to vaccinate 3360 high-risk individuals, to prevent one hospitalization and 60,471 high-risk individuals to prevent one death. Conclusion The yearly influenza vaccination campaigns had a sustained positive benefit for the high-risk population, reducing hospitalizations and deaths. These results can support public health plans toward increased vaccine coverage in high-risk groups.

scholarly journals Possible Impact of Wide-scale Vaccination Against Serogroup B Neisseria Meningitidis on Gonorrhea Incidence Rates in One Region of Quebec, Canada

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S734-S735 ◽  
Author(s):  
Jean Longtin ◽  
Rejean Dion ◽  
Marc Simard ◽  
Jean-Francois Betala Belinga ◽  
Yves Longtin ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Vaccine Coverage ◽  
Vaccination Campaign ◽  
Age Groups ◽  
Incidence Rates ◽  
Study Objective ◽  
Grant Recipient ◽  
Invasive Infections ◽  
Wide Scale ◽  
The Impact

Abstract Background Owing to a persistent increase of serogroup B Neisseria meningitidis (Nm) invasive infections in the Saguenay-Lac-Saint-Jean (SLSJ) region of the province of Quebec (Canada) since 2006, a wide-scale vaccination campaign of individuals aged 6 months to 20 years was conducted between May and December 2014 using the 4-component protein-based meningococcus serogroup B vaccine (4CMenB). Components of this vaccine have shown to potentially cross-react with Neisseria gonorrhoeae (Ng). The study objective was to assess the impact of the vaccination campaign on Ng incidence rate (IR). Methods Ng cases notified to public health authorities during prevaccination period (January 2006 to June 2014) and postvaccination period (July 2014 to June 2017) were analyzed. The impact of this mass campaign was estimated by a Poisson regression model, including the year (11 July–June categories), age (14–20 vs. 21 years and older), and the intervention (0 by default and 1 in those 14–20 years in the period of July 2014 to June 2017). Results Overall vaccine coverage was 82% in the target group. A total of 231 Ng cases were reported among persons 14 years and older (IR: 8.4/100,000 person-years) of the SLSJ region from January 2006 to June 2017. A decrease in the Ng number of cases and IR among individuals 14–20 years was observed during the post-vaccination period whereas it increased in those 21 years and older (figure). Estimate of vaccination impact was an Ng risk reduction of 59% (95% CI: −22% to 84%; P = 0.1). During the same period, Chlamydia trachomatis (Ct) infections increased among persons of both age groups in the SLSJ region. Conclusion Although the estimate of the impact of the campaign was not statistically significant, possibly due to limited size of the study population and the low incidence of the disease, it is congruent with results of a case–control study in New Zealand showing an OMV-MeNZB vaccine effectiveness of 31%. A higher effectiveness of 4CMenB is a plausible hypothesis as three additional proteins also found in Ng are included in the vaccine used in the SLSJ region. The results of this ecologic study suggest cross-protection of 4CMenB vaccine against Ng infections. Further studies on this topic are warranted. Disclosures P. De Wals, GlaxoSmithKline: Grant Investigator and Scientific Advisor, Grant recipient and travel expenses. Pfizer: Grant Investigator and Scientific Advisor, Grant recipient and travel expenses. Sanofi-Pasteur: Grant Investigator and Scientific Advisor, Grant recipient and travel expenses. Novartis: Grant Investigator and Scientific Advisor, Grant recipient and travel expenses.

scholarly journals Impact of vaccination on the incidence of measles in Mozambique in the period 2000 to 2011

2013 ◽  
Vol 29 (2) ◽  
pp. 257-269 ◽  
Author(s):  
Artur Manuel Muloliwa ◽  
Luiz Antonio Bastos Camacho ◽  
José Fernando Souza Verani ◽  
Taynãna César Simões ◽  
Martinho do Carmo Dgedge
Keyword(s):  
Vaccine Coverage ◽  
Incidence Rates ◽  
Measles Elimination ◽  
High Incidence ◽  
Maputo City ◽  
Measles Vaccination ◽  
Coverage Rates ◽  
Vaccination Campaigns ◽  
Measles Incidence ◽  
The Impact

The aim of this study was to contribute to the better planning of measles elimination actions in Mozambique, by considering the impact of vaccination actions over the period 2000 to 2011. Descriptive and ecological studies and case records made available by the Ministry of Health were used to analyze measles vaccination coverage. Statistical analysis was performed using time series and spatial analysis. Vaccine coverage rates ranged from 82% to 99%. Coverage rates in Maputo city were under 70% and in Niassa province they were over 100%. Coverage showed a clustered pattern in the districts. The measles incidence rate was 1.58 per 100,000 inhabitants (0.00-40.08 per 100,000 inhabitants); districts bordering neighboring countries presented high incidence rates. Although measles morbidity and mortality has decreased in Mozambique, vaccine coverage has been insufficient to interrupt measles transmission. Enhanced surveillance, including investigation of cases and outbreaks, and improvements in measles vaccination are recommended in order to achieve a homogenous coverage rate of ≥ 95% for both routine and mass vaccination campaigns.

Pertussis in England and Wales: an investigation of transmission dynamics and control by mass vaccination

1989 ◽  
Vol 236 (1284) ◽  
pp. 213-252 ◽  
Keyword(s):  
Mathematical Models ◽  
Vaccine Efficacy ◽  
Case Reports ◽  
Mass Vaccination ◽  
Vaccine Uptake ◽  
Transmission Dynamics ◽  
England And Wales ◽  
Epidemic Period ◽  
The Impact ◽  
Induced Immunity

The epidemiology of pertussis and its prospects for control by mass vaccination in England and Wales are investigated by analyses of longitudinal records on incidence and vaccine uptake, and horizontal data on age-stratified case reports. Mathematical models of the transmission dynamics of the infection that incorporate loss of natural and vaccine-induced immunity plus variable vaccine efficacy are developed, and their predictions compared with observed trends. Analyses of case reports reveal that the individual force of infection is age dependent, with peak transmission in the 5- to 10-year-old age class. A model incorporating this age dependency, along with partial vaccine efficacy and loss of vaccine-induced immunity, generates predicted patterns that best mirror observed trends since mass vaccination was inaugurated in 1957 in England and Wales. Model projections accurately mirror the failure of mass vaccination to increase the inter-epidemic period of the infection (three years) over that pertaining before control. The analysis suggests that this is due to the impact of partial vaccine efficacy. Projected trends to not accurately reflect the low levels of pertussis incidence reported between epidemics in the periods of high vaccine uptake. This is thought to arise from a combination of factors, including loss of natural and vaccine induced immunity, biases in case reporting (where reporting efficiency is positively associated with the incidence of pertussis), and seasonal variations in transmission. Model predictions suggest that the vaccination of 88% of each birth cohort before the age of 1 year will eliminate bacterial transmission, provided the vaccine confers lifelong protection against infection. If vaccine-induced immunity is significantly less than lifelong (or if vaccination fails to protect all its recipients) repeated cohort immunization is predicted to be necessary to eliminate transmission. Future research needs are discussed, and emphasis is placed on the need for more refined data on vaccine efficacy, the duration of natural and vaccine-induced immunity and the incidence of clinical pertussis and subclinical infections (perhaps by the development of reliable serological tests). Future mathematical models will need especially to incorporate seasonality in transmission.

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.

scholarly journals Impact of Rotavirus Vaccine on Premature Infants

2014 ◽  
Vol 21 (10) ◽  
pp. 1404-1409 ◽  
Author(s):  
Jean-Michel Roué ◽  
Emmanuel Nowak ◽  
Grégoire Le Gal ◽  
Thomas Lemaitre ◽  
Emmanuel Oger ◽  
...  
Keyword(s):  
Premature Infants ◽  
Vaccine Coverage ◽  
Vaccination Campaign ◽  
University Hospital ◽  
Vaccination Program ◽  
National Study ◽  
Rotavirus Vaccine ◽  
Term Infants ◽  
Rotavirus Diarrhea ◽  
The Impact

ABSTRACTInfants born preterm are at a higher risk of complications and hospitalization in cases of rotavirus diarrhea than children born at term. We evaluated the impact of a rotavirus vaccination campaign (May 2007 to May 2010) on hospitalizations for rotavirus gastroenteritis in a population of children under 3 years old born prematurely (before 37 weeks of gestation) in the Brest University Hospital birth zone. Active surveillance from 2002 to 2006 and a prospective collection of hospitalizations for rotavirus diarrhea were initiated in the pediatric units of Brest University Hospital until May 2010. Numbers of hospitalizations for rotavirus diarrhea among the population of children born prematurely, before and after the start of the vaccination program, were compared using a Poisson regression model controlling for epidemic-to-epidemic variation. A total of 217 premature infants were vaccinated from 2007 to 2010. Vaccine coverage for a complete course of three doses was 41.9%. The vaccine safety in premature infants was similar to that in term infants. The vaccination program led to a division by a factor of 2.6 (95% confidence interval [CI], 1.3 to 5.2) in the number of hospitalizations for rotavirus diarrhea during the first two epidemic seasons following vaccine introduction and by a factor of 11 (95% CI, 3.5 to 34.8) during the third season. We observed significant effectiveness of the pentavalent rotavirus vaccine on the number of hospitalizations in a population of prematurely born infants younger than 3 years of age. A multicenter national study would provide better assessment of this impact. (This study [Impact of Systematic Infants Vaccination Against Rotavirus on Gastroenteritis Hospitalization: a Prospective Study in Brest District, France (IVANHOE)] has been registered at ClinicalTrials.gov under registration no. NCT00740935.)

scholarly journals Improved Temporal Trends of Vaccination Coverage Rates in Childhood after the Mandatory Vaccination Act, Italy 2014–2019

2021 ◽  
Vol 10 (12) ◽  
pp. 2540
Author(s):  
Michela Sabbatucci ◽  
Anna Odone ◽  
Carlo Signorelli ◽  
Andrea Siddu ◽  
Francesco Maraglino ◽  
...  
Keyword(s):  
Vaccine Coverage ◽  
Temporal Trends ◽  
Herd Immunity ◽  
Haemophilus Influenzae Type ◽  
Childhood Immunization ◽  
Vaccine Preventable Diseases ◽  
Immunization Rates ◽  
Health Strategy ◽  
Coverage Rates ◽  
The Impact

Maintaining high vaccine coverage (VC) for pediatric vaccinations is crucial to ensure herd immunity, reducing the risk of vaccine-preventable diseases (VPD). The Italian vaccination Law (n. 119/2017) reinforced mandates for polio, diphtheria, tetanus, and hepatitis B, extending the mandate to pertussis, Haemophilus influenzae type b, chickenpox, measles, mumps, and rubella, for children up to 16 years of age. We analyzed the national temporal trends of childhood immunization rates from 2014 to 2019 to evaluate the impact of the mandatory reinforcement law set in 2017 as a sustainable public health strategy in Italy. In a 3-year period, 9 of the 10 compulsory vaccinations reached the threshold of 95% and VC for chicken pox increased up to 90.5%, significantly. During the same period, the recommended vaccinations (against meningococcus B and C, pneumococcus, and rotavirus) also recorded a significant increase in VC trends. In conclusion, although the reinforcement of compulsory vaccination generated a wide public debate that was amplified by traditional and social media, the 3-year evaluation highlights positive results.

scholarly journals Modeling the impact of COVID-19 vaccination in Lebanon: A call to speed-up vaccine roll out

2021 ◽  
Author(s):  
Ghina R Mumtaz ◽  
Fadi El-Jardali ◽  
Mathilda Jabbour ◽  
Aya Harb ◽  
Laith J Abu-Raddad ◽  
...  
Keyword(s):  
Vaccine Coverage ◽  
Vaccination Campaign ◽  
Scale Up ◽  
High Coverage ◽  
Social Distancing ◽  
Epidemic Curve ◽  
Limited Health ◽  
Care Capacity ◽  
The Impact ◽  
Roll Out

Background: Amidst a very difficult economic and political situation, and after a large first SARS-CoV-2 wave near the end of 2020, Lebanon launched its vaccination campaign on 14 February 2021. To date, only 6.7% of the population have received at least one dose of the vaccine, raising serious concerns over the speed of vaccine roll-out and its impact in the event of a future surge. Objective: Using mathematical modeling, we assessed the short-term impact (by end of 2021) of various vaccine roll-out scenarios on SARS-CoV-2 epidemic course in Lebanon. Results: At current immunity levels in the population, estimated by the model at 40% on 15 April 2021, a large epidemic wave is predicted if all social distancing restrictions are gradually eased and variants of concern are introduced. Reaching 80% vaccine coverage by end of 2021 will flatten the epidemic curve and will result in a 37% and 34% decrease in the peak daily numbers of severe/critical disease cases and deaths, respectively; while reaching intermediate coverage of 40% will result in only 10-11% decrease in each. Reaching 80% coverage by end of 2021 will avert 3 times more hospitalizations and deaths over the course of this year compared with 40% coverage. Impact of vaccination was substantially enhanced with rapid scale-up. Reaching 80% vaccine coverage by August would prevent twice as many severe/critical disease cases and deaths than if it were reached by December. Finally, a longer duration over which restrictions are eased resulted in a more favorable impact of vaccination. Conclusion: For vaccination to have an impact on the predicted epidemic course and associated disease burden in Lebanon, vaccination has to be rapid and reach high coverage (at least 70%), while sustaining social distancing measures during roll-out. At current vaccination pace, this is unlikely to be achieved. Concerted efforts need to be put to overcome local challenges and substantially scale up vaccination to avoid a surge that the country, with its multiple crises and limited health-care capacity, is largely unprepared for.

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