The need for pre-emptive control strategies for mpox in Asia and Oceania

Introduction:The transmission dynamics of the recent mpox outbreak highlights the lack of infrastructure available to rapidly respond to novel STI outbreaks,of which Asia and Oceania remains particularly susceptible.Here,we simulate outbreaks in this setting and propose the use of pre-emptive vaccination within the men who have sex with men(MSM)community before the arrival and establishment of the virus.Materials and methods Using data driven heterogeneous sexual contact networks,we simulated outbreaks of mpox in Singapore,Hong Kong,and Sydney.An individual based SEIR compartmental model was used to simulate epidemic trajectories and the impact of different vaccination uptakes was assessed in their ability to avert or suppress outbreaks upon the arrival of mpox within the MSM populations.Results:The highly dense sexual networks of Singapore and Sydney experience rapid outbreaks,with infection peaks occurring at day 41 and 23 respectively,compared to Hong Kong which occurs at day 77.Across the simulations with no vaccination,68.2%–89.7%of the MSM community will become infected with mpox across the different cities,over a simulation period of 1 year.By implementing vaccination strategies,the infection rate across the cities can be reduced to as low as 3.1%of the population(range:3.1%–82.2%)depending on the implementation and uptake of the vaccine.Vaccination is also extremely effective in slowing the start of the epidemic,delaying the epidemic peak by 36–50 days in Hong Kong,or even preventing the outbreak of mpox.Discussion:With extremely dense and well-connected sexual contact networks,where 65.2%–83.2%of the population are connected to a super-spreader in the different contact networks,pre-emptive or immediate vaccination upon identification of the first case is strongly recommended to help better manage the outbreak of mpox and prevent potential straining of healthcare systems.

EpiMix:A novel method to estimate effective reproduction number

Transmission potential of a pathogen,often quantified by the time-varying reproduction number R t,provides the current pace of infection for a disease and indicates whether an emerging epidemic is under control.In this study,we proposed a novel method,EpiMix,for R t estimation,wherein we incorporated the impacts of exogenous factors and random effects under a Bayesian regression framework.Using Integrated Nested Laplace Approx-imation,EpiMix is able to efficiently generate reliable,deterministic R t estimates.In the simulations and case studies performed,we further demonstrated the method's robust-ness in low-incidence scenarios,together with other merits,including its flexibility in selecting variables and tolerance of varying reporting rates.All these make EpiMix a potentially useful tool for real-time R t estimation provided that the serial interval distri-bution,time series of case counts and external influencing factors are available.

Urban-Rural Disparities for COVID-19:Evidence from 10 Countries and Areas in the Western Pacific

Background.Limited evidence on the effectiveness of various types of social distancing measures,from voluntary physical distancing to a community-wide quarantine,exists for the Western Pacific Region(WPR)which has large urban and rural populations.Methods.We estimated the time-varying reproduction number(Rt)in a Bayesian framework using district-level mobility data provided by Facebook(i)to assess how various social distancing policies have contributed to the reduction in transmissibility of SARS-COV-2 and(ii)to examine within-country variations in behavioural responses,quantified by reductions in mobility,for urban and rural areas.Results.Social distancing measures were largely effective in reducing transmissibility,with Rt estimates decreased to around the threshold of 1.Within-country analysis showed substantial variation in public compliance across regions.Reductions in mobility were significantly lower in rural and remote areas than in urban areas and metropolitan cities(p<0:001)which had the same scale of social distancing orders in place.Conclusions.Our findings provide empirical evidence that public compliance and consequent intervention effectiveness differ between urban and rural areas in the WPR.Further work is required to ascertain the factors affecting these differing behavioural responses,which can assist in policy-making efforts and increase public compliance in rural areas where populations are older and have poorer access to healthcare.