Biology subjects

Brooks-Pollock, E.

Publications and source records attributed to Brooks-Pollock, E..

4 recordsLinked to original sources

bioRxiv2019

A model of tuberculosis clustering in low incidence countries reveals more on-going transmission in the United Kingdom than the Netherlands between 2010 and 2015.

Tuberculosis (TB) is a major public health threat, including in low TB incidence countries, through a combination of imported infection and onward transmission. Using data from the Enhanced Tuberculosis Surveillance system in the United Kingdom (UK) and the Netherlands (NL) Tuberculosis Register, we developed a mathematical model of TB importation and transmission in low-incidence settings. We apply this method to compare the effective reproduction number for TB, the contribution of importation and the role of superspreaders in the UK and the NL. We estimate that on average, between 2010 and 2015, a TB case generated 0{middle dot}41(0{middle dot}30,0{middle dot}60) secondary cases in the UK, and 0{middle dot}24(0{middle dot}14,0{middle dot}48) secondary cases in the NL. A majority of cases did not generate any secondary cases. Recent transmission accounted for 26% (21%,36%) of UK cases and 19%(11%,31%) of NL cases. We predict that reducing UK transmission rates to those observed in NL would result in 538(266,818) fewer cases annually in the UK. This methodology reveals common transmission mechanisms across two low-incidence countries and can be applied to other settings. Control policies aimed at limiting spread have a role to play in eliminating TB in low incidence countries.

epidemiology↗

bioRxiv2019

Reassessing the Evidence for Universal School-age Bacillus Calmette Guerin (BCG) Vaccination in England and Wales

BackgroundIn 2005, England and Wales switched from universal BCG vaccination against tuberculosis (TB) disease for school-age children to targeted vaccination of neonates. We assessed the quantitative evidence that informed this policy change.\n\nMethodsWe recreated a previous approach for estimating the impact of ending the BCG schools scheme in England and Wales, updating the model with parameter uncertainty. We investigated scenarios considered by the UKs Joint Committee on Vaccination and Immunisation, and explored new approaches using notification data. We estimated the number of vaccines needed to prevent a single notification, and the average annual additional notifications caused by ending the BCG schools scheme.\n\nResultsWe found a 1.9% annual decrease in TB incidence rates best matched notification data. We estimate that 1600 (2.5-97.5% Quantiles (Q): 1300 - 2100) vaccines would have been required to prevent a single notification in 2004. If the scheme had ended in 2001, 302 (2.5-97.5% Q: 238 - 369) additional annual notifications would have occurred compared to if the scheme had continued. If the scheme ended in 2016, 120 (2.5-97.5% Q: 88 - 155) additional annual notifications would have occurred.\n\nConclusionsOur estimates of the impact of ending the BCG schools scheme were highly sensitive to the annual decrease in incidence rates. The impact of ending the BCG schools scheme was found to be greater than previously thought when parameter values were updated and notification data were used. Our results highlight the importance of including uncertainty when forecasting the impact of changes in vaccination policy.\n\nWhat is already known on this subjectO_LITargeted Bacillus Calmette Guerin (BCG) vaccination against TB is recommended in low incidence countries over universal vaccination.\nC_LIO_LIThe impact of replacing universal BCG vaccination in England and Wales with a targeted programme in 2005 was assessed under the assumption of static declines in TB rates.\nC_LIO_LIThe BCG Guerin vaccine was shown to be effective in the UK born in England, regardless of the age at which it was given. School-age vaccination maybe more beneficial in this population than in other settings.\nC_LI\n\nWhat this study addsO_LIUsing notification data from England and Wales from 1973 to 2015, we estimate that the ending the BCG schools scheme likely resulted in more additional cases than was predicted.\nC_LIO_LIThe inclusion of parameter uncertainty, and measurement error, allowed the uncertainty in the final estimates to be presented. Previously published estimates may have been spuriously precise.\nC_LIO_LIThis study highlights the need for a more detailed evaluation of the 2005 change in BCG policy. In particular, the impact of including the introduction of targeted neonatal vaccination and capturing the long term, indirect, effects needs further study.\nC_LI

epidemiology↗

bioRxiv2019

Estimating the effect of the 2005 change in BCG policy in England: A retrospective cohort study

BackgroundIn 2005, England changed from universal Bacillus Calmette-Guerin (BCG) vaccination of school-age children to targeted BCG vaccination of high-risk children at birth.\n\nMethodsWe combined notification data from the Enhanced Tuberculosis Surveillance system, with demographic data from the Labour Force Survey to construct retrospective cohorts of individuals in England relevant to both the universal, and targeted vaccination programmes between Jan 1, 2000 and Dec 31, 2010. For each cohort, we estimated incidence rates over a 5 year follow-up period and used Poisson and Negative Binomial regression models in order to estimate the impact of the change in policy on TB.\n\nResultsIn the non-UK born, we found evidence for an association between a reduction in incidence rates and the change in BCG policy (school-age IRR: 0.74 (95%CI 0.61, 0.88), neonatal IRR: 0.62 (95%CI 0.44, 0.88)). We found some evidence that the change in BCG policy was associated with a increase in incidence rates in the UK born school-age population (IRR: 1.08 (95%CI 0.97, 1.19)) and weaker evidence of an association with a reduction in incidence rates in UK born neonates (IRR: 0.96 (95%CI 0.82, 1.14)). Overall, we found that the change in BCG policy was associated with directly preventing 385 (95% CI -105, 881) TB cases.\n\nConclusionsWithdrawing universal vaccination at school-age and targeting BCG vaccination towards high-risk neonates was associated with reduced incidence of TB in England. This was largely driven by reductions in the non-UK born. There was a slight increase in UK born school-age cases.\n\nKey MessagesO_LIThere is little existing literature on the impact of withdrawing universal school-age BCG vaccination and introducing high-risk neonatal BCG vaccination on TB incidence rates in the populations directly affected by the vaccination programmes.\nC_LIO_LIThere was strong evidence that the change in policy was associated with a decrease in TB incidence rates in non-UK born neonates and school-age children. In the UK born individuals, there was some evidence that the change in policy was associated with an increase in TB incidence rates in those relevant to the universal school-age scheme, with little evidence of a decrease in incidence rates in those relevant to the high-risk neonatal vaccination scheme.\nC_LIO_LIOverall the change in vaccination policy was associated with preventing TB cases, mainly in the non-UK born.\nC_LIO_LIThese results provide an important evaluation of the direct effects of both withdrawing and implementing a BCG vaccination programme in a low incidence, high income, country and are relevant to several other countries that have made similar changes to their vaccination programmes.\nC_LI

epidemiology↗

bioRxiv2018

Exploring the effects of BCG vaccination in patients diagnosed with tuberculosis: observational study using the Enhanced Tuberculosis Surveillance system

BackgroundBacillus Calmette-Guerin (BCG) is one of the most widely-used vaccines worldwide. BCG primarily reduces the progression from infection to disease, however there is evidence that BCG may provide additional benefits. We aimed to investigate whether there is evidence in routinely-collected surveillance data that BCG vaccination impacts outcomes for tuberculosis (TB) cases in England.\n\nMethodsWe obtained all TB notifications for 2009-2015 in England from the Enhanced Tuberculosis surveillance system. We considered five outcomes: All-cause mortality, death due to TB (in those who died), recurrent TB, pulmonary disease, and sputum smear status. We used logistic regression, with complete case analysis, to investigate each outcome with BCG vaccination, years since vaccination and age at vaccination, adjusting for potential confounders. All analyses were repeated using multiply imputed data.\n\nResultsWe found evidence of an association between BCG vaccination and reduced all-cause mortality (aOR:0.76 (95%CI 0.64 to 0.89), P:0.001) and weak evidence of an association with reduced recurrent TB (aOR:0.90 (95%CI 0.81 to 1.00), P:0.056). Analyses using multiple imputation suggested that the benefits of vaccination for all-cause mortality were reduced after 10 years.\n\nConclusionsWe found that BCG vaccination was associated with reduced all-cause mortality in people with TB although this benefit was less pronounced more than 10 years after vaccination. There was weak evidence of an association with reduced recurrent TB.\n\nHighlightsO_LIFound evidence of an association between BCG vaccination and reduced all-cause mortality in TB cases.\nC_LIO_LIWeaker evidence of an association between BCG vaccination and reduced repeat TB episodes in TB cases.\nC_LIO_LIThere was little evidence of an association with other TB outcomes.\nC_LIO_LIWe explored the identified associations by age and time since vaccination.\nC_LI

epidemiology↗