What does 95% COVID-19 vaccine efficacy really mean?

Olliaro, Piero

doi:10.1016/s1473-3099(21)00075-x

Cited by 37 publications

(33 citation statements)

References 2 publications

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“…The problem does not appear to be confined to popular outlets since, as pointed out by Olliaro (2021) , incorrect interpretation of the significance of VE can also be found in prestigious scientific journals, including an editorial in Lancet Infectious Diseases:…”

Section: Introduction: the (Non-obvious) Concept Of Vaccine Efficacymentioning

confidence: 99%

The misunderstanding of vaccine efficacy

Tentori

Passerini

Timberlake

et al. 2021

Social Science & Medicine

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Although the efficacies of vaccines against SARS-CoV-2, i.e., the virus that causes Covid-19, have been publicized and praised, and although they are assumed to encourage vaccine compliance, little is known about how well these figures are understood by the general public. Our study aims to fill this gap by investigating whether laypeople have an adequate grasp of what vaccine efficacy means and, if not, which misconceptions and consequences are the most common. To this end, we carried out three online behavioral experiments involving 1800 participants overall. The first, exploratory experiment, with a sample of 600 UK participants, allowed us to document by means of both an open-ended question and a multiple-choice question, a common misinterpretation of the efficacy of SARS-CoV-2 vaccines as the non-incidence rate among the vaccinated. We formally demonstrated that this error leads to a systematic overestimation of the probability of individuals who are vaccinated developing Covid-19. The second experiment confirmed the prevalence of this misinterpretation in a new sample of 600 UK and Italian participants, by means of a slightly different multiple-choice question that included more response options. Finally, in a third experiment, involving another 600 UK and Italian participants, we investigated the behavioral implications of the documented error and showed that it might undermine the general positive attitude toward vaccines as well as the intention to get vaccinated. On the whole, the results of this study reveal a general misunderstanding of vaccine efficacy that may have serious consequences for the perceived benefits of SARS-CoV-2 vaccines and, thus, the willingness to be vaccinated.

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Section: Introduction: the (Non-obvious) Concept Of Vaccine Efficacymentioning

confidence: 99%

The misunderstanding of vaccine efficacy

Tentori

Passerini

Timberlake

et al. 2021

Social Science & Medicine

View full text Add to dashboard Cite

show abstract

“…It is essential to understand the efficacy of the approved vaccines (originated from Asia). The approved vaccines have shown efficacy in clinical trials, and it is essential as it protects both the person and a country's population [53,54]. In general, it was observed that most of the approved COVID-19 vaccines had efficacy in the range of 70-95% (Table 1).…”

Section: The Effectiveness Of the Approved Vaccines Originated From Asiamentioning

confidence: 99%

Asian-Origin Approved COVID-19 Vaccines and Current Status of COVID-19 Vaccination Program in Asia: A Critical Analysis

et al. 2021

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COVID-19 vaccination has started throughout the globe. The vaccination program has also begun in most Asian countries. This paper analyzed the Asian-origin COVID-19 vaccines and vaccination program status in Asia till March 2021 under three sections. In the first section, we mapped the approved vaccines that originated from Asia, their technological platforms, collaborations during vaccine development, and regulatory approval from other countries. We found that a total of eight Asian COVID-19 vaccines originated and got approval from three countries: China, India, and Russia. In the second section, we critically evaluated the recent progress of COVID-19 vaccination programs. We analyzed the overall vaccination status across the Asian region. We also calculated the cumulative COVID-19 vaccine doses administered in different Asian countries, vaccine rolling in 7-day average in various Asian countries, and COVID-19 vaccine per day doses administrated in several Asian countries. We found that China and India vaccinated the maximum number of people. Finally, we evaluated the factors affecting the COVID-19 vaccination program in Asia, such as vaccine hesitancy, basic reproduction numbers (R0) and vaccination campaigns, and the cost of the vaccines. Our analysis will assist the implementation of the COVID-19 vaccination program successfully in Asia.

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“…Since the first day, the Italian ministry of health, through the special pandemic commissioner, publishes daily the vaccination data on a GitHub data repository (Italian Special Pandemic Commissioner, 2021) that provides an in-depth vision of both the delivered and administered doses. in preventing the hospitalization of an infected person (Anand and Stahel, 2021;Benenson et al, 2021;Olliaro, 2021;Vasileiou et al, 2021). Since the second wave of Covid-19, which started in Italy at the beginning of October 2020 (as of May 2021, Italy is experiencing the deflation trend of the third wave, which started towards the end of February 2021), Covid-19 patients die only in hospitals (Ciminelli and Garcia-Mandicó, 2020).…”

Section: An Alternative Approach To Vaccinationmentioning

confidence: 99%

“…Specifically, the 32 tt  interval is 7, 14, and 14 days for Pfizer/BioNTech, Moderna, and Vaxzevria vaccines respectively (Mansourabadi et al, 2020;Olliaro, 2021).…”

Section: Immunization Profilementioning

confidence: 99%

Alternative Vaccination Politics

Manca

Benincasa

2021

Preprint

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Background: The timely implementation of the vaccination campaign and sharp rules for vaccine administration can make a difference. The paper investigates the impact of alternative policies based on scientific vaccination priorities inspired by the extended statistics on Covid-19 fatalities.Methods: In the case of Covid-19 vaccination, a principal role is played by promptly adopting a reverse-order of age approach (to target first the elderly) coupled to covering the high priority categories but postponing the low priority ones. We implemented an in silico vaccination simulator capable of comparing what happened in reality with what might have happened if alternative vaccination policies had been adopted. The immunization profile and the death distribution curve allowed measuring the distance between reality and alternative policies and finally quantifying the expected number of saved lives.Results: The alternative approach to vaccination was applied to Italy and Lombardy that host 60 and 10 million residents respectively. In about 100 days of vaccination based on (a) a reverse-order of age policy (from 90+ to 80-89 to 70-79 year-olds, etc.), (b) vaccination of priority categories, (c) postponement of non-priority categories and reallocation of such doses to (a) and (b), the saved lives would have been 3969 in Italy (of which 799 in Lombardy). In the same period, Italy suffered 30,911 fatalities (of which 5,613 in Lombardy). Of those fatalities, about 12.8% in Italy and 14.2% in Lombardy might have been avoided if a different approach to vaccination had been applied. Even better results would have been achieved if the elderly vaccination had been anticipated a few days (which started only 53 days after the very beginning of the Italian vaccination campaign) or if the vaccination engine had performed better in terms of daily administered doses while respecting the available delivered doses.Conclusions: A different approach to the vaccination politics based on sharp and straight policies based on scientific quantitative data of Covid-19 mortality as a function of age and comorbidities would have accomplished a better quantitative effect on extinguishing the pandemic and containing the fatalities toll.

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What does 95% COVID-19 vaccine efficacy really mean?

Cited by 37 publications

References 2 publications

The misunderstanding of vaccine efficacy

The misunderstanding of vaccine efficacy

Asian-Origin Approved COVID-19 Vaccines and Current Status of COVID-19 Vaccination Program in Asia: A Critical Analysis

Alternative Vaccination Politics

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