scholarly journals Model-informed COVID-19 vaccine prioritization strategies by age and serostatus

2020 ◽  
Author(s):  
Kate M Bubar ◽  
Kyle Reinholt ◽  
Stephen M Kissler ◽  
Marc Lipsitch ◽  
Sarah Cobey ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Cumulative Incidence ◽  
Acquired Immunity ◽  
Years Of Life Lost ◽  
Serological Tests ◽  
Transmission Blocking ◽  
Individual Level ◽  
Transmission Rates ◽  
Effective Transmission ◽  
Transmission Blocking Vaccine

Limited initial supply of SARS-CoV-2 vaccine raises the question of how to prioritize available doses. Here, we used a mathematical model to compare five age-stratified prioritization strategies. A highly effective transmission-blocking vaccine prioritized to adults ages 20-49 years minimized cumulative incidence, but mortality and years of life lost were minimized in most scenarios when the vaccine was prioritized to adults over 60 years old. Use of individual-level serological tests to redirect doses to seronegative individuals improved the marginal impact of each dose while partially addressing existing inequities in COVID-19 impact. While maximum impact prioritization strategies were broadly consistent across countries, transmission rates, vaccination rollout speeds, and estimates of naturally acquired immunity, this framework can be used to compare impacts of prioritization strategies across contexts.

scholarly journals Model-informed COVID-19 vaccine prioritization strategies by age and serostatus

Science ◽  
2021 ◽  
Vol 371 (6532) ◽  
pp. 916-921 ◽  
Author(s):  
Kate M. Bubar ◽  
Kyle Reinholt ◽  
Stephen M. Kissler ◽  
Marc Lipsitch ◽  
Sarah Cobey ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Severe Acute Respiratory Syndrome ◽  
Cumulative Incidence ◽  
Acquired Immunity ◽  
Years Of Life Lost ◽  
Serological Tests ◽  
Individual Level ◽  
Transmission Rates ◽  
Effective Transmission ◽  
Transmission Blocking Vaccine

Limited initial supply of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine raises the question of how to prioritize available doses. We used a mathematical model to compare five age-stratified prioritization strategies. A highly effective transmission-blocking vaccine prioritized to adults ages 20 to 49 years minimized cumulative incidence, but mortality and years of life lost were minimized in most scenarios when the vaccine was prioritized to adults greater than 60 years old. Use of individual-level serological tests to redirect doses to seronegative individuals improved the marginal impact of each dose while potentially reducing existing inequities in COVID-19 impact. Although maximum impact prioritization strategies were broadly consistent across countries, transmission rates, vaccination rollout speeds, and estimates of naturally acquired immunity, this framework can be used to compare impacts of prioritization strategies across contexts.

Naturally acquired immunity to sexual stageP. falciparumparasites

Parasitology ◽  
2016 ◽  
Vol 143 (2) ◽  
pp. 187-198 ◽  
Author(s):  
WILL J. R. STONE ◽  
KATHLEEN W. DANTZLER ◽  
SANDRA K. NILSSON ◽  
CHRIS J. DRAKELEY ◽  
MATTHIAS MARTI ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Acquired Immunity ◽  
Transmission Blocking ◽  
Erythrocyte Surface ◽  
Antibody Titres ◽  
Specific Proteins ◽  
Specialized Form ◽  
Transmission Stage ◽  
Effective Transmission ◽  
Transmission Blocking Vaccine

SUMMARYGametocytes are the specialized form ofPlasmodiumparasites that are responsible for human-to-mosquito transmission of malaria. Transmission of gametocytes is highly effective, but represents a biomass bottleneck for the parasite that has stimulated interest in strategies targeting the transmission stages separately from those responsible for clinical disease. Studying targets of naturally acquired immunity against transmission-stage parasites may reveal opportunities for novel transmission reducing interventions, particularly the development of a transmission blocking vaccine (TBV). In this review, we summarize the current knowledge on immunity against the transmission stages ofPlasmodium. This includes immune responses against epitopes on the gametocyte-infected erythrocyte surface during gametocyte development, as well as epitopes present upon gametocyte activation in the mosquito midgut. We present an analysis of historical data on transmission reducing immunity (TRI), as analysed in mosquito feeding assays, and its correlation with natural recognition of sexual stage specific proteins Pfs48/45 and Pfs230. Although high antibody titres towards either one of these proteins is associated with TRI, the presence of additional, novel targets is anticipated. In conclusion, the identification of novel gametocyte-specific targets of naturally acquired immunity against different gametocyte stages could aid in the development of potential TBV targets and ultimately an effective transmission blocking approach.

scholarly journals How effective was Newfoundland & Labrador’s travel ban to prevent the spread of COVID-19? An agent-based analysis

2021 ◽  
Author(s):  
Dionne M. Aleman ◽  
Benjamin Z. Tham ◽  
Sean J. Wagner ◽  
Justin Semelhago ◽  
Asghar Mohammadi ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Spatial Location ◽  
Contact Tracing ◽  
Infection Rates ◽  
Case Scenario ◽  
Agent Based ◽  
Individual Level ◽  
Transmission Rates ◽  
Imported Cases ◽  
The Uk

AbstractBackgroundTo prevent the spread of COVID-19 in Newfoundland & Labrador (NL), NL implemented a wide travel ban in May 2020. We estimate the effectiveness of this travel ban using a customized agent-based simulation (ABS).MethodsWe built an individual-level ABS to simulate the movements and behaviors of every member of the NL population, including arriving and departing travellers. The model considers individual properties (spatial location, age, comorbidities) and movements between environments, as well as age-based disease transmission with pre-symptomatic, symptomatic, and asymptomatic transmission rates. We examine low, medium, and high travel volume, traveller infection rates, and traveller quarantine compliance rates to determine the effect of travellers on COVID spread, and the ability of contact tracing to contain outbreaks.ResultsInfected travellers increased COVID cases by 2-52x (8-96x) times and peak hospitalizations by 2-49x (8-94x), with (without) contact tracing. Although contact tracing was highly effective at reducing spread, it was insufficient to stop outbreaks caused by travellers in even the best-case scenario, and the likelihood of exceeding contact tracing capacity was a concern in most scenarios. Quarantine compliance had only a small impact on COVID spread; travel volume and infection rate drove spread.InterpretationNL’s travel ban was likely a critically important intervention to prevent COVID spread. Even a small number of infected travellers can play a significant role in introducing new chains of transmission, resulting in exponential community spread and significant increases in hospitalizations, while outpacing contact tracing capabilities. With the presence of more transmissible variants, e.g., the UK variant, prevention of imported cases is even more critical.

scholarly journals Evaluation of two lead malaria transmission blocking vaccine candidate antibodies in natural parasite-vector combinations

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Anais Bompard ◽  
Dari F. Da ◽  
Rakiswendé S. Yerbanga ◽  
Sumi Biswas ◽  
Melissa Kapulu ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Vaccine Candidate ◽  
Transmission Blocking ◽  
Transmission Blocking Vaccine

Antibodies to Plasmodium vivax transmission-blocking vaccine candidate antigens Pvs25 and Pvs28 do not show synergism

Vaccine ◽  
2001 ◽  
Vol 20 (5-6) ◽  
pp. 763-770 ◽  
Author(s):  
Hajime Hisaeda ◽  
William E. Collins ◽  
Allan Saul ◽  
Anthony W. Stowers
Keyword(s):  
Plasmodium Vivax ◽  
Vaccine Candidate ◽  
Transmission Blocking ◽  
Transmission Blocking Vaccine
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