Free and perfectly safe but only partially effective vaccines can harm everyone

Abstract

Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre -including this research content -immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

Do Face Masks Create a False Sense of Security? A COVID-19 Dilemma

“…If people who would otherwise stay home and engage in social distancing cease that behavior because they wear masks, then recommendations to wear masks in public may be creating a perverse incentive. Others have pointed out that partially effective vaccines can lead to increased infection, especially given assortative mixing patterns (Talamàs and Vohra 2020). We should expect a similar phenomenon for face masks.…”

An imperfect test for a virus can Be worse than No test at all

“…Likewise, it is unclear how allowing agents to make more sophisticated decisionsletting them choose not just whether to isolate but also with whom to interact-would affect the findings. Given the results of Talamàs and Vohra (2020), it is reasonable to suspect that a similar destabilizing effect could manifest as the result of an imperfect test.…”

“…A number of other recent papers have pointed out other counterintuitive incentives in models of epidemics and disease transmission. Those include Talamàs and Vohra (2020), who show that the introduction of a moderately effective vaccine can result in Pareto losses in welfare for society; and Heinsalu (2020), who illustrates that increasing the infection risk early in a pandemic may be optimal. However, the mechanism behind the result in Talamàs and Vohra (2020) is completely different to that in this paper.…”

“…Those include Talamàs and Vohra (2020), who show that the introduction of a moderately effective vaccine can result in Pareto losses in welfare for society; and Heinsalu (2020), who illustrates that increasing the infection risk early in a pandemic may be optimal. However, the mechanism behind the result in Talamàs and Vohra (2020) is completely different to that in this paper. There, the authors assume a network structure and allow agents to choose with whom they match.…”

Vaccine Hesitancy, Passports and the Demand for Vaccination

“…However, while this is possible in terms of exposure probabilities, the fact that infected agents and susceptible agents are restricted to the same activities means that the probability that a given agent a susceptible agent encounters is infected is equal to the portion of infected people in the population unadjusted for activity level. Thus, following the spirit of analyses such as Kremer (1996) and Talamàs and Vohra (2020), it is reasonable to suppose that the probability of infection remains at most βxI(t).…”