Agent -- Increased transmissibility with variants (more likely to bind receptor cells, higher VL, ? longer infectiousness)
Host -- increased immunity, ? increase in contacts with release of restrictions
Environment -- seasonal changes
Many models seem to directly assume that increased transmissibility will increase transmission and will increase case counts at population level.
But transmissibility is not the only determinant of transmission. Ie, see the epidemiological triad from two tweets ago.
Increased transmissibility could enhance replacement where variants become dominant forms of SARS-CoV-2 and still not increase transmission to the point of dramatically changing the trajectory of cases and associated morbidity and mortality.
I think that's what will happen.
My optimism doesn't change the need for active public health strategies.
I am just cheerier as I go about that work.
So let us: 1) get people vaccinated 2) reinvest in public health infrastructure, IPAC in health/work places 3) Improve structural supports for folks on margins
Potential Indicators: 1) Hospitalization/Severity rates by VOC compared to wild-type 2) Evidence of changing trajectory of hospitalization/ICU admissions over coming weeks. 3) IPAC adherence in businesses that remain open 4) VOC case counts by exposure type to inform reopening
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Respiratory viruses are seasonal 2ary to immunity, population, and environmental determinants.
However, I was unprepared for how controversial discussing potential seasonality of seasonal hCoVs would be
1/4
Goals of discussing seasonality:
1) Facilitate empiric interpretation of the effects of Wave 1 restriction-based strategies 2) Prepare for Wave 2 with data-driven interventions responding to inequities nearly universally observed explained by living and working conditions.
2/4
Let's discuss this and much more:
1) Correlates of exposure/immunity (humoral & cellular markers) 2) Optimal mask interventions (who, where, why, how) to maximize population-level incidence reduction 3) Mandates vs guidelines facilitated by resources 4) Fear vs empowerment
3/4
Intended to help to do independent critical appraisal of the data being released in #COVID19 including an overview of study designs.
Also to help you assess whether "experts" did critical appraisal or are just repeating abstract
Quantitative Study Designs
Only covering studies where unit of analysis is an individual person.
There are also ecological studies which use a population as the level of analysis and systematic reviews & meta analyses which quantitatively combine results of several studies.
Observational Studies - Descriptive
Examples: case reports, case-series reports, surveillance studies, surveys
Cross-sectional studies - Describe the prevalence of a disease or other phenomena without looking for associations between variables