Multiscale model for forecasting Sabin 2 vaccine virus household and community transmission

Since the global withdrawal of Sabin 2 oral poliovirus vaccine (OPV) from routine immunization, the Global Polio Eradication Initiative (GPEI) has reported multiple circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreaks. Here, we generated an agent-based, mechanistic model designed to assess OPV-related vaccine virus transmission risk in populations with heterogeneous immunity, demography, and social mixing patterns. To showcase the utility of our model, we present a simulation of mOPV2-related Sabin 2 transmission in rural Matlab, Bangladesh based on stool samples collected from infants and their household contacts during an mOPV2 clinical trial. Sabin 2 transmission following the mOPV2 clinical trial was replicated by specifying multiple, heterogeneous contact rates based on household and community membership. Once calibrated, the model generated Matlab-specific insights regarding poliovirus transmission following an accidental point importation or mass vaccination event. We also show that assuming homogeneous contact rates (mass action), as is common of poliovirus forecast models, does not accurately represent the clinical trial and risks overestimating forecasted poliovirus outbreak probability. Our study identifies household and community structure as an important source of transmission heterogeneity when assessing OPV-related transmission risk and provides a calibratable framework for expanding these analyses to other populations. Trial Registration: ClinicalTrials.gov This trial is registered with clinicaltrials.gov, NCT02477046.

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Mechanistic theory predicts the effects of temperature and humidity on inactivation of SARS-CoV-2 and other enveloped viruses

eLife ◽

10.7554/elife.65902 ◽

2021 ◽

Vol 10 ◽

Author(s):

Dylan H Morris ◽

Kwe Claude Yinda ◽

Amandine Gamble ◽

Fernando W Rossine ◽

Qishen Huang ◽

...

Keyword(s):

Mechanistic Model ◽

Virus Transmission ◽

Mitigation Strategies ◽

Transmission Risk ◽

Mechanistic Study ◽

Enveloped Viruses ◽

Temperature And Humidity ◽

Inert Surface ◽

Human Coronaviruses ◽

The Stability

Ambient temperature and humidity strongly affect inactivation rates of enveloped viruses, but a mechanistic, quantitative theory of these effects has been elusive. We measure the stability of SARS-CoV-2 on an inert surface at nine temperature and humidity conditions and develop a mechanistic model to explain and predict how temperature and humidity alter virus inactivation. We find SARS-CoV-2 survives longest at low temperatures and extreme relative humidities (RH); median estimated virus half-life is >24 hours at 10C and 40% RH, but ~1.5 hours at 27C and 65% RH. Our mechanistic model uses fundamental chemistry to explain why inactivation rate increases with increased temperature and shows a U-shaped dependence on RH. The model accurately predicts existing measurements of five different human coronaviruses, suggesting that shared mechanisms may affect stability for many viruses. The results indicate scenarios of high transmission risk, point to mitigation strategies, and advance the mechanistic study of virus transmission.

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Community structure mediates Sabin 2 polio vaccine virus transmission

10.1101/2020.07.01.20144501 ◽

2020 ◽

Cited By ~ 1

Author(s):

M Famulare ◽

W Wong ◽

R Haque ◽

JA Platts-Mills ◽

P Saha ◽

...

Keyword(s):

Community Structure ◽

Contact Structure ◽

Virus Transmission ◽

Social Contact ◽

Vaccine Virus ◽

Mass Action ◽

Routine Immunization ◽

Disease Forecasting ◽

Forecasting Models

AbstractSince the global withdrawal of Sabin 2 oral poliovirus vaccine (OPV) from routine immunization, the Global Polio Eradication Initiative (GPEI) has reported multiple circulating vaccine-derived poliovirus type 2 (cVDPV2) outbreaks. cVDPV2 outbreaks are controlled using mass vaccination with Sabin 2 OPV, which carries a small, but serious risk of seeding future cVDPV2 outbreaks in settings of low population immunity. Accurate forecasting models are essential to quantify transmission and reversion risk to optimize effectiveness of mass OPV2 campaigns and minimize cVDPV2 emergence risk. Here, we developed an agent-based model of Sabin 2 vaccine transmission to simulate and to assess the role of household community structure on transmission during a clinical trial designed to monitor community transmission following a mass OPV campaign in Matlab, Bangladesh. Our results emphasize the role of household and community membership and shows that vaccine virus transmission occurs primarily between local community members. When constructing disease forecasting models, ignoring community structure and asserting mass action systematically overestimates emergence probability, duration, and epidemic size due to mechanistic differences in how transmissions are distributed. Model forecasting of vaccine transmission and cVDPV2 emergence risk must incorporate existing knowledge regarding community and social contact structure to provide accurate assessments of transmission risk and ensure the efficacy of future cVDPV2 containment and prevention strategies.Significance StatementThe emergence of multiple Sabin 2 circulating, vaccine-derived poliovirus (cVDPV2) outbreaks since the withdrawal of Sabin 2 oral poliovirus from routine immunization scales threatens to undermine global eradication efforts. Disease forecasting models are invaluable tools for evaluating transmission and outbreak risk but it is unclear how relevant social behavior and household community model is for cVDPV2 outbreak forecasting. Understanding the interaction between social contact structure and disease transmission is critical for accurate risk assessment but is frequently ignored in outbreak forecast models. Our study utilizes data from a cluster-randomized vaccine trial designed to trace Sabin 2 vaccine virus transmission to assess whether model forecasts that ignore social community structure are appropriate for informing public policy.

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The final stages of the global eradication of poliomyelitis

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0140 ◽

2013 ◽

Vol 368 (1623) ◽

pp. 20120140 ◽

Cited By ~ 51

Author(s):

Nicholas C. Grassly

Keyword(s):

Virus Transmission ◽

Polio Eradication ◽

Oral Poliovirus Vaccine ◽

Intestinal Immunity ◽

Oral Vaccination ◽

Wild Poliovirus ◽

Global Polio Eradication Initiative ◽

Global Eradication ◽

Lower Income Countries

The global incidence of poliomyelitis has dropped by more than 99 per cent since the governments of the world committed to eradication in 1988. One of the three serotypes of wild poliovirus has been eradicated and the remaining two serotypes are limited to just a small number of endemic regions. However, the Global Polio Eradication Initiative (GPEI) has faced a number of challenges in eradicating the last 1 per cent of wild-virus transmission. The polio endgame has also been complicated by the recognition that vaccination with the oral poliovirus vaccine (OPV) must eventually cease because of the risk of outbreaks of vaccine-derived polioviruses. I describe the major challenges to wild poliovirus eradication, focusing on the poor immunogenicity of OPV in lower-income countries, the inherent limitations to the sensitivity and specificity of surveillance, the international spread of poliovirus and resulting outbreaks, and the potential significance of waning intestinal immunity induced by OPV. I then focus on the challenges to eradicating all polioviruses, the problem of vaccine-derived polioviruses and the risk of wild-type or vaccine-derived poliovirus re-emergence after the cessation of oral vaccination. I document the role of research in the GPEI's response to these challenges and ultimately the feasibility of achieving a world without poliomyelitis.

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Virus Transmission Risk in Urban Rail Systems: Microscopic Simulation-Based Analysis of Spatio-Temporal Characteristics

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/03611981211010181 ◽

2021 ◽

pp. 036119812110101

Author(s):

Jiali Zhou ◽

Haris N. Koutsopoulos

Keyword(s):

Public Transportation ◽

Virus Transmission ◽

Flow Characteristics ◽

Transportation Systems ◽

Transmission Risk ◽

Microscopic Simulation ◽

Spatial And Temporal Patterns ◽

Subway System ◽

Public Transportation Systems ◽

The Impact

The transmission risk of airborne diseases in public transportation systems is a concern. This paper proposes a modified Wells-Riley model for risk analysis in public transportation systems to capture the passenger flow characteristics, including spatial and temporal patterns, in the number of boarding and alighting passengers, and in number of infectors. The model is used to assess overall risk as a function of origin–destination flows, actual operations, and factors such as mask-wearing and ventilation. The model is integrated with a microscopic simulation model of subway operations (SimMETRO). Using actual data from a subway system, a case study explores the impact of different factors on transmission risk, including mask-wearing, ventilation rates, infectiousness levels of disease, and carrier rates. In general, mask-wearing and ventilation are effective under various demand levels, infectiousness levels, and carrier rates. Mask-wearing is more effective in mitigating risks. Impacts from operations and service frequency are also evaluated, emphasizing the importance of maintaining reliable, frequent operations in lowering transmission risks. Risk spatial patterns are also explored, highlighting locations of higher risk.

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Some lessons for malaria from the Global Polio Eradication Initiative

Malaria Journal ◽

10.1186/s12936-021-03690-6 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Matiana González-Silva ◽

N. Regina Rabinovich

Keyword(s):

Polio Eradication ◽

Vaccine Virus ◽

Surveillance Systems ◽

Polio Virus ◽

History Of ◽

Eradication Campaign ◽

Global Polio Eradication Initiative ◽

Governance Strategy ◽

Malaria Eradication ◽

Near Future

AbstractThe Global Polio Eradication Initiative (GPEI) was launched in 1988 with the aim of completely clearing wild polio viruses by 2000. More than three decades later, the goal has not been achieved, although spectacular advances have been made, with wild polio virus reported in only 2 countries in 2019. In spite of such progress, novel challenges have been added to the equation, most importantly outbreaks of vaccine-derived polio cases resulting from reversion to neurovirulence of attenuated vaccine virus, and insufficient coverage of vaccination. In the context of the latest discussions on malaria eradication, the GPEI experience provides more than a few lessons to the malaria field when considering a coordinated eradication campaign. The WHO Strategic Advisory Committee on Malaria Eradication (SAGme) stated in 2020 that in the context of more than 200 million malaria cases reported, eradication was far from reach in the near future and, therefore, efforts should remain focused on getting back on track to achieve the objectives set by the Global Technical Strategy against Malaria (2016–2030). Acknowledging the deep differences between both diseases and the stages they are in their path towards eradication, this paper draws from the history of GPEI and highlights relevant insights into what it takes to eradicate a pathogen in fields as varied as priority setting, global governance, strategy, community engagement, surveillance systems, and research. Above all, it shows the critical need for openness to change and adaptation as the biological, social and political contexts vary throughout the time an eradication campaign is ongoing.

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Immunogenicity and Safety of Inactivated Sabin-Strain Polio Vaccine “PoliovacSin”: Clinical Trials Phase I and II

Vaccines ◽

10.3390/vaccines9060565 ◽

2021 ◽

Vol 9 (6) ◽

pp. 565

Author(s):

Anastasia Piniaeva ◽

Georgy Ignatyev ◽

Liubov Kozlovskaya ◽

Yury Ivin ◽

Anastasia Kovpak ◽

...

Keyword(s):

Clinical Trial ◽

Clinical Trials ◽

Phase I ◽

Safety Profile ◽

Neutralizing Antibody ◽

Polio Eradication ◽

Controlled Clinical Trial ◽

Double Blind ◽

Good Tolerability ◽

Poliomyelitis Vaccine

Global polio eradication requires both safe and effective vaccines, and safe production processes. Sabin oral poliomyelitis vaccine (OPV) strains can evolve to virulent viruses and result in poliomyelitis outbreaks, and conventional inactivated poliomyelitis vaccine (Salk-IPV) production includes accumulation of large stocks of neurovirulent wild polioviruses. Therefore, IPV based on attenuated OPV strains seems a viable option. To increase the global supply of affordable inactivated vaccine in the still not-polio free world we developed an IPV made from the Sabin strains–PoliovacSin. Clinical trials included participants 18–60 years of age. A phase I single-center, randomized, double-blind placebo-controlled clinical trial included 60 participants, who received one dose of PoliovacSin or Placebo. A phase II multicenter, randomized, double-blind, comparative clinical trial included 200 participants, who received one dose of PoliovacSin or Imovax Polio. All vaccinations were well tolerated, and PoliovacSin had a comparable safety profile to the Placebo or the reference Imovax Polio preparations. A significant increase in neutralizing antibody levels to polioviruses types 1–3 (Sabin and wild) was observed in PoliovacSin and Imovax Polio vaccinated groups. Therefore, clinical trials confirmed good tolerability, low reactogenicity, and high safety profile of the PoliovacSin and its pronounced immunogenic properties. The preparation was approved for clinical trials involving infants.

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Application of Hazard Analysis of Critical Control Points (HACCP) Method to Describe Critical Points in Healthcare Waste Management of Razi Hospital in Ghaemshahr, Iran During COVID-19 Pandemic in 2020

Jundishapur Journal of Health Sciences ◽

10.5812/jjhs.114939 ◽

2021 ◽

Vol 13 (3) ◽

Author(s):

Seyedeh Fatemeh Erfaneh Mousavi ◽

Fathollah Gholami-Borujeni

Keyword(s):

Waste Management ◽

Direct Contact ◽

Hazard Analysis ◽

Virus Transmission ◽

Transmission Risk ◽

Control Points ◽

Healthcare Waste ◽

Critical Control Points ◽

Healthcare Waste Management ◽

Corrective Actions

Background: During the outbreak of COVID-19 in developing countries such as Iran, the management of healthcare waste has become a very important issue. It is necessary to investigate the risk of virus transmission through direct contact, inhalation, and environmental pollution to reduce transmission risk. The Hazard Analysis of Critical Control Points framework is used to simplify quick responses of waste management for facing the novel infectious disease. Objectives: The aim of this study was to use risk analysis frameworks to describe hazard critical control points (HACCP) and make recommendations and corrective actions for staff who work in healthcare facilities and communities experiencing the COVID-19 outbreak. Methods: In the present descriptive-analytical study, a team of environmental health experts identified the critical control points of healthcare waste produced in Razi Hospital and divided them into three categories and six steps. A tested and verified hazard analysis flow diagram was prepared to determine critical points in different steps of healthcare waste management. Critical control points were identified and analyzed by the team at each step. Recommendations and corrective actions were made for each control point. Results: The production rate significantly increased from 580 to 1,733 kg per day, probably caused by the increased use of disposable waste during the pandemic. Transportation, disinfection, and storage appeared to be associated with an individually high level of transmission risk of COVID-19 virus. Also, direct contact with infectious waste was often associated with a high risk of virus transmission. In the final disposal of healthcare waste, people were exposed to a lower level of risk. Conclusions: Training staff in different wards of the hospital to use proper personal protective equipment (PPE), hand washing, disinfectants, and ventilation could reduce the risk of COVID-19 transmission through healthcare waste. Using the HACCP method for providing recommendations and corrective actions could simplify responses to reduce the transmission risk of COVID-19 during pandemics.

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Estimating the impact of reopening schools on the reproduction number of SARS-CoV-2 in England, using weekly contact survey data

BMC Medicine ◽

10.1186/s12916-021-02107-0 ◽

2021 ◽

Vol 19 (1) ◽

Author(s):

James D. Munday ◽

Christopher I. Jarvis ◽

Amy Gimma ◽

Kerry L. M. Wong ◽

Kevin van Zandvoort ◽

...

Keyword(s):

Reproduction Number ◽

Transmission Rate ◽

Transmission Risk ◽

Individual Level ◽

Face To Face ◽

School Settings ◽

Contact Rates ◽

Contact Survey ◽

The Uk ◽

The Impact

Abstract Background Schools were closed in England on 4 January 2021 as part of increased national restrictions to curb transmission of SARS-CoV-2. The UK government reopened schools on 8 March. Although there was evidence of lower individual-level transmission risk amongst children compared to adults, the combined effects of this with increased contact rates in school settings and the resulting impact on the overall transmission rate in the population were not clear. Methods We measured social contacts of > 5000 participants weekly from March 2020, including periods when schools were both open and closed, amongst other restrictions. We combined these data with estimates of the susceptibility and infectiousness of children compared with adults to estimate the impact of reopening schools on the reproduction number. Results Our analysis indicates that reopening all schools under the same measures as previous periods that combined lockdown with face-to-face schooling would be likely to increase the reproduction number substantially. Assuming a baseline of 0.8, we estimated a likely increase to between 1.0 and 1.5 with the reopening of all schools or to between 0.9 and 1.2 reopening primary or secondary schools alone. Conclusion Our results suggest that reopening schools would likely halt the fall in cases observed between January and March 2021 and would risk a return to rising infections, but these estimates relied heavily on the latest estimates or reproduction number and the validity of the susceptibility and infectiousness profiles we used at the time of reopening.

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Resolved Hepatitis B: Achieved or Imaginary Wellbeing?

Russian Journal of Gastroenterology Hepatology Coloproctology ◽

10.22416/1382-4376-2021-31-1-7-19 ◽

2021 ◽

Vol 31 (1) ◽

pp. 7-19

Author(s):

S. N. Batskikh

Keyword(s):

Hepatitis B ◽

Liver Diseases ◽

Clinical Signs ◽

Virus Transmission ◽

Hbv Infection ◽

Transmission Risk ◽

Viral Dna ◽

Occult Hbv Infection ◽

Occult Hbv ◽

Hbsag Clearance

Aim. Assessment of the clinical impact of previous hepatitis B infection (PHB).Key points. PHB is characterized by the presence of viral DNA in the organism (including intrahepatic cccDNA and integrated DNA). Possible virus persistence in the PHB patient's hepatocytes potentiates the agent transmission risk via haemotransfusion, organ transplantation and haemodialysis. Occult HBV infection in PHB individuals can reactivate at background immunosuppressive or chemotherapies. PHB with chronic liver diseases of various aetiology significantly rises the risk of cirrhosis and hepatic cancer. The PHB association with autoimmune liver diseases and extrahepatic gastrointestinal cancer needs a careful research to confirm the possible involvement of hepatitis B virus in morbid genesis.Conclusion. No clinical signs of acute or chronic disease, HBsAg clearance and negative viral DNA load in blood of PHB individuals do not necessarily imply a complete disease eradication.PHB elicitation improves accuracy of the overall prognosis, reduces the virus transmission risk and prevents the reactivation of HBV infection.

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Vector distribution and transmission risk of the Zika virus in South and Central America

PeerJ ◽

10.7717/peerj.7920 ◽

2019 ◽

Vol 7 ◽

pp. e7920

Author(s):

Sarah Cunze ◽

Judith Kochmann ◽

Lisa K. Koch ◽

Elisa Genthner ◽

Sven Klimpel

Keyword(s):

South America ◽

Central America ◽

Zika Virus ◽

Habitat Suitability ◽

Virus Transmission ◽

Transmission Risk ◽

Eastern Coast ◽

Suitable Habitat ◽

Virus Infections ◽

Vector Species

Background Zika is of great medical relevance due to its rapid geographical spread in 2015 and 2016 in South America and its serious implications, for example, certain birth defects. Recent epidemics urgently require a better understanding of geographic patterns of the Zika virus transmission risk. This study aims to map the Zika virus transmission risk in South and Central America. We applied the maximum entropy approach, which is common for species distribution modelling, but is now also widely in use for estimating the geographical distribution of infectious diseases. Methods As predictor variables we used a set of variables considered to be potential drivers of both direct and indirect effects on the emergence of Zika. Specifically, we considered (a) the modelled habitat suitability for the two main vector species Aedes aegypti and Ae. albopictus as a proxy of vector species distributions; (b) temperature, as it has a great influence on virus transmission; (c) commonly called evidence consensus maps (ECM) of human Zika virus infections on a regional scale as a proxy for virus distribution; (d) ECM of human dengue virus infections and, (e) as possibly relevant socio-economic factors, population density and the gross domestic product. Results The highest values for the Zika transmission risk were modelled for the eastern coast of Brazil as well as in Central America, moderate values for the Amazon basin and low values for southern parts of South America. The following countries were modelled to be particularly affected: Brazil, Colombia, Cuba, Dominican Republic, El Salvador, Guatemala, Haiti, Honduras, Jamaica, Mexico, Puerto Rico and Venezuela. While modelled vector habitat suitability as predictor variable showed the highest contribution to the transmission risk model, temperature of the warmest quarter contributed only comparatively little. Areas with optimal temperature conditions for virus transmission overlapped only little with areas of suitable habitat conditions for the two main vector species. Instead, areas with the highest transmission risk were characterised as areas with temperatures below the optimum of the virus, but high habitat suitability modelled for the two main vector species. Conclusion Modelling approaches can help estimating the spatial and temporal dynamics of a disease. We focused on the key drivers relevant in the Zika transmission cycle (vector, pathogen, and hosts) and integrated each single component into the model. Despite the uncertainties generally associated with modelling, the approach applied in this study can be used as a tool and assist decision making and managing the spread of Zika.

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