Two inoculations with a new SARS-CoV-2 mRNA-based vaccine that encodes a protein in the coronavirus spike elicited high titers of virus-neutralizing antibody in healthy adult volunteers. ...Virus-specific T-cell responses were also elicited. Interim findings indicated that a dose of 100 μg per injection maximized immune response and minimized the reactogenicity of the vaccine.
The mRNA-1273 vaccine was approved for emergency use in December 2020; trial participants who received placebo were informed of the results and offered vaccination. At the close of the blinded phase ...of the trial, the vaccine efficacy in preventing Covid-19 illness was 93.2%, and the efficacy against severe disease was 98.2%. No new safety issues were identified.
Abstract
Background
Global vaccine development efforts have been accelerated in response to the devastating coronavirus disease 2019 (COVID-19) pandemic. We evaluated the impact of a 2-dose COVID-19 ...vaccination campaign on reducing incidence, hospitalizations, and deaths in the United States.
Methods
We developed an agent-based model of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission and parameterized it with US demographics and age-specific COVID-19 outcomes. Healthcare workers and high-risk individuals were prioritized for vaccination, whereas children under 18 years of age were not vaccinated. We considered a vaccine efficacy of 95% against disease following 2 doses administered 21 days apart achieving 40% vaccine coverage of the overall population within 284 days. We varied vaccine efficacy against infection and specified 10% preexisting population immunity for the base-case scenario. The model was calibrated to an effective reproduction number of 1.2, accounting for current nonpharmaceutical interventions in the United States.
Results
Vaccination reduced the overall attack rate to 4.6% (95% credible interval CrI: 4.3%–5.0%) from 9.0% (95% CrI: 8.4%–9.4%) without vaccination, over 300 days. The highest relative reduction (54%–62%) was observed among individuals aged 65 and older. Vaccination markedly reduced adverse outcomes, with non-intensive care unit (ICU) hospitalizations, ICU hospitalizations, and deaths decreasing by 63.5% (95% CrI: 60.3%–66.7%), 65.6% (95% CrI: 62.2%–68.6%), and 69.3% (95% CrI: 65.5%–73.1%), respectively, across the same period.
Conclusions
Our results indicate that vaccination can have a substantial impact on mitigating COVID-19 outbreaks, even with limited protection against infection. However, continued compliance with nonpharmaceutical interventions is essential to achieve this impact.
Vaccination with a 95% efficacy against disease could substantially mitigate future attack rates, hospitalizations, and deaths, even if only adults are vaccinated. Nonpharmaceutical interventions remain an important part of outbreak response as vaccines are distributed over time.
Enteric Fever — Tools for Prevention Neuzil, Kathleen M.
The New England journal of medicine,
04/2023, Letnik:
388, Številka:
16
Journal Article
Recenzirano
Typhoid and paratyphoid fever are acquired through consumption of water or food contaminated by the feces of an infected or colonized person. Although improvements in sewage disposal and the ...provision of safe drinking water eliminated enteric fever in much of the industrialized world by the early 20th century, typhoid and paratyphoid fever remain endemic in impoverished regions of Asia, Africa, and Oceania. Estimating the burden of these diseases is challenging, given their nonspecific clinical presentation and the lack of blood-culture surveillance in much of the world. In this issue of the
Journal
, John et al.
1
report the results of a . . .
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a member of a diverse family of enveloped, nonsegmented RNA viruses. The coronavirus genomic RNA is unusually large, the RNA polymerase ...is error-prone, and mutations accumulate with increasing frequency during infections. With continued uncontrolled transmission and viral replication, mutations that give the virus a fitness advantage will emerge. A SARS-CoV-2 variant of concern has one or more mutations that confer worrisome epidemiologic, immunologic, or pathogenic properties.
1
From early in the pandemic, South Africa has been a global leader in the use of intensive genomic sequencing to identify and track emerging SARS-CoV-2 mutations. . . .
Ad26.COV2.S vaccine is a replication-incompetent human adenovirus type 26 vector containing the gene sequence that produces SARS-CoV-2 spike protein in a prefusion-stabilized conformation. In a ...randomized trial involving nearly 40,000 persons, vaccine efficacy was 66% against moderate to severe–critical Covid-19 and 85% against severe–critical Covid-19. Efficacy against the variant first identified in South Africa was 64% against moderate disease and 82% against severe–critical disease.
By analyzing publicly available surveillance data from 2011-2016, we produced country-specific estimates of seasonal influenza activity for 118 countries in the six World Health Organization regions. ...Overall, the average country influenza activity period was 4.7 months. Our analysis characterized 100 countries (85%) with one influenza peak season, 13 (11%) with two influenza peak seasons, and five (4%) with year-round influenza activity. Surveillance data were limited for many countries. These data provide national estimates of influenza activity, which may guide planning for influenza vaccination implementation, program timing and duration, and policy development.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutations may diminish vaccine-induced protective immune responses, particularly as antibody titers wane over time. Here, we assess the ...effect of SARS-CoV-2 variants B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.429 (Epsilon), B.1.526 (Iota), and B.1.617.2 (Delta) on binding, neutralizing, and angiotensin-converting enzyme 2 (ACE2)–competing antibodies elicited by the messenger RNA (mRNA) vaccine mRNA-1273 over 7 months. Cross-reactive neutralizing responses were rare after a single dose. At the peak of response to the second vaccine dose, all individuals had responses to all variants. Binding and functional antibodies against variants persisted in most subjects, albeit at low levels, for 6 months after the primary series of the mRNA-1273 vaccine. Across all assays, B.1.351 had the lowest antibody recognition. These data complement ongoing studies to inform the potential need for additional boost vaccinations.
In accompanying papers (P. L. Acosta, M. T. Caballero, and F. P. Polack, Clin Vaccine Immunol 23:189-195, 2016, http://dx.doi.org/10.1128/CVI.00609-15; M. Vissers, I. M. L. Ahout, M. I. de Jonge, and ...G. Ferwerda, Clin Vaccine Immunol 23:243-245, 2016, http://dx.doi.org/10.1128/CVI.00590-15) in this issue of Clinical and Vaccine Immunology, the history of and immune mechanisms underlying vaccine-enhanced respiratory syncytial virus (RSV) disease and of investigations of mucosal antibodies and their association with viral load in RSV-infected children, respectively, are described. This commentary discusses RSV vaccine candidates, target populations, and the challenges associated with achieving a safe and effective vaccine.
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