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3.
Math Biosci ; 337: 108621, 2021 07.
Article in English | MEDLINE | ID: covidwho-1207058

ABSTRACT

When allocating limited vaccines to control an infectious disease, policy makers frequently have goals relating to individual health benefits (e.g., reduced morbidity and mortality) as well as population-level health benefits (e.g., reduced transmission and possible disease eradication). We consider the optimal allocation of a limited supply of a preventive vaccine to control an infectious disease, and four different allocation objectives: minimize new infections, deaths, life years lost, or quality-adjusted life years (QALYs) lost due to death. We consider an SIR model with n interacting populations, and a single allocation of vaccine at time 0. We approximate the model dynamics to develop simple analytical conditions characterizing the optimal vaccine allocation for each objective. We instantiate the model for an epidemic similar to COVID-19 and consider n=2 population groups: one group (individuals under age 65) with high transmission but low mortality and the other group (individuals age 65 or older) with low transmission but high mortality. We find that it is optimal to vaccinate younger individuals to minimize new infections, whereas it is optimal to vaccinate older individuals to minimize deaths, life years lost, or QALYs lost due to death. Numerical simulations show that the allocations resulting from our conditions match those found using much more computationally expensive algorithms such as exhaustive search. Sensitivity analysis on key parameters indicates that the optimal allocation is robust to changes in parameter values. The simple conditions we develop provide a useful means of informing vaccine allocation decisions for communicable diseases.


Subject(s)
Epidemics/prevention & control , Mass Vaccination , Models, Theoretical , Viral Vaccines , Adult , Age Factors , Aged , Aged, 80 and over , COVID-19/prevention & control , Humans , Mass Vaccination/methods , Mass Vaccination/standards , Middle Aged , Viral Vaccines/administration & dosage , Viral Vaccines/supply & distribution , Young Adult
4.
Vaccine ; 38(34): 5418-5423, 2020 07 22.
Article in English | MEDLINE | ID: covidwho-1135582

ABSTRACT

The World Health Organization declared the COVID-19 disease as a pandemic requiring a rapid response. Through online search, direct communication with network members and an internal survey, engagements of developing countries' vaccine manufacturers' network members in the research and development of COVID-19 vaccines and their capacities in the manufacturing, fill-finish and distribution of vaccines were assessed. Currently, 19 network members engaged in research and development of COVID-19 vaccines, using six principal technology platforms. In addition, an internal survey showed that the number of vaccines supplied collectively by 37 members, in 2018-19, was about 3.5 billion doses annually. Almost a third of network members having vaccines prequalified by the World Health Organization comply with international regulations and mechanisms to distribute vaccines across borders. The use of existing manufacturing, fill-finish and distribution capabilities can support an efficient roll-out of vaccines against COVID-19, while maintaining supply security of existing vaccines for on-going immunization programmes.


Subject(s)
Biomedical Research/organization & administration , Coronavirus Infections , Drug Industry/organization & administration , International Cooperation , Pandemics , Pneumonia, Viral , Viral Vaccines/supply & distribution , COVID-19 , COVID-19 Vaccines , Clinical Trials as Topic , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Humans , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Viral Vaccines/immunology , World Health Organization
8.
Nature ; 586(7830): 516-527, 2020 10.
Article in English | MEDLINE | ID: covidwho-982728

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported in late 2019 in China and is the causative agent of the coronavirus disease 2019 (COVID-19) pandemic. To mitigate the effects of the virus on public health, the economy and society, a vaccine is urgently needed. Here I review the development of vaccines against SARS-CoV-2. Development was initiated when the genetic sequence of the virus became available in early January 2020, and has moved at an unprecedented speed: a phase I trial started in March 2020 and there are currently more than 180 vaccines at various stages of development. Data from phase I and phase II trials are already available for several vaccine candidates, and many have moved into phase III trials. The data available so far suggest that effective and safe vaccines might become available within months, rather than years.


Subject(s)
Coronavirus Infections , Drug Development , Pandemics , Pneumonia, Viral , Viral Vaccines , Animals , COVID-19 , COVID-19 Vaccines , Clinical Trials as Topic , Coronavirus Infections/immunology , Coronavirus Infections/prevention & control , Coronavirus Infections/virology , Drug Industry , Humans , Immunity, Mucosal , Pneumonia, Viral/immunology , Pneumonia, Viral/virology , Viral Vaccines/adverse effects , Viral Vaccines/immunology , Viral Vaccines/supply & distribution
9.
Sci Rep ; 10(1): 21594, 2020 12 09.
Article in English | MEDLINE | ID: covidwho-966852

ABSTRACT

Present hopes to conquer the Covid-19 epidemic are largely based on the expectation of a rapid availability of vaccines. However, once vaccine production starts, it will probably take time before there is enough vaccine for everyone, evoking the question how to distribute it best. While present vaccination guidelines largely focus on individual-based factors, i.e. on the question to whom vaccines should be provided first, e.g. to risk groups or to individuals with a strong social-mixing tendency, here we ask if a strategic spatiotemporal distribution of vaccines, e.g. to prioritize certain cities, can help to increase the overall survival rate of a population subject to an epidemic disease. To this end, we propose a strategy for the distribution of vaccines in time and space, which sequentially prioritizes regions with the most new cases of infection during a certain time frame and compare it with the standard practice of distributing vaccines demographically. Using a simple statistical model we find that, for a locally well-mixed population, the proposed strategy strongly reduces the number of deaths (by about a factor of two for basic reproduction numbers of [Formula: see text] and by about 35% for [Formula: see text]). The proposed vaccine distribution strategy establishes the idea that prioritizing individuals not only regarding individual factors, such as their risk of spreading the disease, but also according to the region in which they live can help saving lives. The suggested vaccine distribution strategy can be tested in more detailed models in the future and might inspire discussions regarding the importance of spatiotemporal distribution rules for vaccination guidelines.


Subject(s)
COVID-19 , Models, Biological , Pandemics , SARS-CoV-2 , Vaccination , Viral Vaccines , COVID-19/mortality , COVID-19/prevention & control , Humans , Viral Vaccines/supply & distribution , Viral Vaccines/therapeutic use
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