Relation between BCG coverage rate and COVID-19 infection worldwide

Macedo, Ana; Febra, Cláudia

doi:10.1016/j.mehy.2020.109816

Cited by 19 publications

(19 citation statements)

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“…A number of publications were published on the subject of BCG vaccination and Covid-19 as this manuscript was under review. These either supported the view that BCG could be protective (Ebina-Shibuya et al 2020;Escobar et al 2020;Hauer et al 2020;Madan et al 2020;Macedo and Febra 2020;Sharma et al 2020), or reported the lack of such an effect (Meena et al 2020;Hamiel et al 2020). However, all studies used datasets from spring.…”

Section: Resultsmentioning

confidence: 58%

BCG vaccination early in life does not improve COVID‐19 outcome of elderly populations, based on nationally reported data

Wassenaar

Buzard²,

Newman³

2020

Lett. Appl. Microbiol.

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Significance and Impact of the Study: It has been suggested in the recent literature that some countries have lower case rates or death rates of Covid-19 as a result of large-scale BCG vaccination programs. This has resulted in the initiation of clinical trials to assess if the vaccine can act as a prophylactic or ameliorate the disease. However, by comparing countries that are well into the epidemic and have different (current or past) BCG vaccination practices, we conclude that there is currently no compelling evidence of any such protective effect.

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Section: Resultsmentioning

confidence: 58%

BCG vaccination early in life does not improve COVID‐19 outcome of elderly populations, based on nationally reported data

Wassenaar

Buzard²,

Newman³

2020

Lett. Appl. Microbiol.

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“…While unpublished, this study had a great impact and gave rise to many comments and follow-up studies (reviewed in 4 ). Some published studies were able to replicate this result 5,6 , but several authors underlined the important statistical flaws inherent to such ecological studies and concluded that randomized controlled trials (RCT) were necessary to address the question 4,7 . As of June 5th 2020, no less than 12 randomized controlled trials (RCTs) studying the protective effect of the BCG against COVID-19 are already registered on https://clinicaltrials.gov/.…”

Section: Introductionmentioning

confidence: 99%

BCG vaccination in infancy does not protect against COVID-19. Evidence from a natural experiment in Sweden

Chaisemartin

2020

Preprint

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Background The Bacille Calmette-Guerin (BCG) tuberculosis vaccine has immunity benefits against respiratory infections. Accordingly, it has been hypothesized that it may have a protective effect against COVID-19. Recent research found that countries with universal BCG childhood vaccination policies tend to be less affected by the COVID-19 pandemic. However, such ecological studies are biased by numerous confounders. Instead, this paper takes advantage of a rare nationwide natural experiment that took place in Sweden in 1975, where discontinuation of newborns BCG vaccination led to a dramatic fall of the BCG coverage rate from 92% to 2% , thus allowing us to estimate the BCG's effect without all the biases associated with cross-country comparisons. Methods Numbers of COVID-19 cases and hospitalizations were recorded for birth cohorts born just before and just after that change, representing 1,026,304 and 1,018,544 individuals, respectively. We used regression discontinuity to assess the effect of BCG vaccination on Covid-19 related outcomes. This method used on such a large population allows for a high precision that would be hard to achieve using a classical randomized controlled trial. Results The odds ratio for Covid-19 cases and Covid-19 related hospitalizations were 0.9997 (CI95: [0.8002-1.1992]) and 1.1931 (CI95: [0.7558-1.6304]), respectively. We can thus reject with 95% confidence that universal BCG vaccination reduces the number of cases by more than 20% and the number of hospitalizations by more than 24% Conclusions While the effect of a recent vaccination must be evaluated, we provide strong evidence that receiving the BCG vaccine at birth does not have a protective effect against COVID-19.

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“…First, global ecological/epidemiological data might have suggested a correlation between MMR vaccination rate and decreased COVID-19 mortality ( 1 ). Some researchers disagreed with this conclusion for the live vaccines including MMR other than BCG ( 2 ). Some countries like Iran and Latin American countries, e.g., Chile, Argentina, and Ecuador, maintaining >90% vaccine coverage, which started BCG vaccination in 1985 or even earlier, still have high mortality from COVID-19 ( 2 , 3 ).…”

Section: Lettermentioning

confidence: 99%

“…Some researchers disagreed with this conclusion for the live vaccines including MMR other than BCG ( 2 ). Some countries like Iran and Latin American countries, e.g., Chile, Argentina, and Ecuador, maintaining >90% vaccine coverage, which started BCG vaccination in 1985 or even earlier, still have high mortality from COVID-19 ( 2 , 3 ). Other possible elements such as individual ACE2 receptor and HLA expressions should be kept in mind.…”

Section: Lettermentioning

confidence: 99%