Thread by @MamaToronto

“Shielding under endemic SARS-CoV-2 conditions is easier said than done: a model-based analysis”

medrxiv.org/content/10.110…

“As the #C19 pandemic continues unabated, many governments & PH bodies worldwide have ceased to implement concerted measures for limiting viral spread, placing the onus instead on the individual…

… In this paper, we examine the feasibility of this proposition using an agent-based model to simulate the impact of individual shielding behaviors on reinfection frequency.”

“Our results suggest that individuals seeking to opt out of adverse outcomes upon SARS-CoV-2 infection will find it challenging to do so, as large reductions in contact rate are required to reduce the risk of infection…

… Our findings suggest the importance of a multilayered strategy for those seeking to reduce the risk of infection.”

“This work also suggests the importance of public health interventions such as universal masking in essential venues and air quality standards to ensure individual freedom of choice regarding COVID-19.”

“At this point, SARS-CoV-2 variants have a very high intrinsic reproductive number (R0), a strong propensity for asymptomatic spread & an ability to evade pre-existing immunity, making disease suppression challenging…

… Meanwhile, many countries have scaled back or abandoned universal PH measures designed to slow SARS-CoV-2 spread”

“Specifically, PH agencies in many countries have removed disease-management measures such as mandatory and/or publicly funded non-pharmaceutical interventions (NPIs: masks, testing, contact tracing, quarantines)”

“A common framing of the public health position in many countries is that managing #C19 infection risk is now a matter of “personal responsibility”. However, the practical feasibility of reducing one’s risk from SARS-CoV-2 through personal protective measures remains an open ?n”

“When it comes to NPIs, one-way masking is substantially less effective than universal masking…

… the removal of mask mandates exposes individuals to unmasked crowds in indoor settings where exposure is unavoidable (such as public transit, schools, grocery stores and medical settings), making it difficult for individuals to opt-out of the additional #C19 risk.”

“At the same time, other NPIs have also been removed: quarantines, testing and social distancing guidelines have been dropped. Meanwhile, improved ventilation has not yet been implemented at scale in Western countries.”

“These changes have occurred even as steps are being taken or called for to reduce outdoor services, and employers have increasingly enforced in-person work (“return to office”) policies leading to outbreaks.”

“Taken together, these changes over the course of the pandemic leaves individuals seeking to reduce their risk of infection with limited options in terms of NPIs.”

“Individuals wishing to mitigate personal COVID-19 risk using biomedical interventions also have limited effective options. At present vaccines have limited efficacy against infection and transmission due to antibody waning and viral immune evasion.”

“Infection also carries a risk of post-acute outcomes (“#LongCovid ”), which is only modestly reduced by vaccination and likely to be a significant driver of public health and societal outcomes with COVID-19”

“At the same time, rapid viral immune evasion has ltd the utility of existing monoclonal antibody prophylactics. Coupled w/ the lack of antiviral prophylactics for SARS-CoV-2, this sitn leaves individuals seeking to reduce their risk of infection w/ few biomedical interventions”

“As a practical matter, individuals seeking to shield have a limited range of interventions available at this point to reduce risk of infection (vaccine boosters, one-way masking and social isolation)…

… and many individuals are forced into high-contact settings as a result of work, school, medical need, or family commitments.”

“As a result, the reduction in contact rate required to limit the risk of infection under unmitigated SARS-CoV-2 transmission is likely to be unachievable for many individuals…

… This highlights the limitations of a public health “individual responsibility” model focused on shielding as a practical strategy for limiting the health costs of COVID-19.”

“In the absence of concerted public health actions to provide options for individuals looking to reduce their risk of infection, shielding as a personal responsibility is challenging to achieve…

… Public health organizations have advocated for oxymoronic “individual public health measures”, but these represent an inadequate solution to the ongoing COVID-19 public health crisis”

“Permitting the unrestrained spread of SARS-CoV-2 in the population will inflict a heavy burden of infection and long COVID on society as a whole, which will be challenging if not impossible for individuals to opt out of in the long run.”

Furthermore from H/T
@arijitchakrav

🧵

https://twitter.com/arijitchakrav/status/1619830719509061632?s=20&t=iurJwaj18XDq7QVZKnSQhA

…

Thank you so very much for your work

#LongCovid
#LongCovidKids

#RealityCheck
#DavosSafe