论文标题
婴儿期的BCG疫苗接种不能预防COVID-19。来自瑞典自然实验的证据
BCG vaccination in infancy does not protect against COVID-19. Evidence from a natural experiment in Sweden
论文作者
论文摘要
Bacille Calmette-Guérin（BCG）结核病疫苗具有免疫力，可抵抗呼吸道感染。因此，已经假设它可能针对Covid-19具有保护作用。最近的研究发现，具有通用芽孢杆菌Calmette-guérin（BCG）儿童疫苗接种政策的国家往往受到COVID-19的大流行的影响较小。但是，这种生态学研究被众多混杂因素偏见。取而代之的是，本文利用了1975年在瑞典进行的一项罕见的全国性自然实验，在1975年，新生儿疫苗接种的停药导致BCG覆盖率从92％降至2％，从而急剧下降，从而使我们能够估算BCG的效果而没有与越野比较相关的所有偏见。在此更改之前和之后，出生的出生队列记录了19例1900案件和住院数量，分别代表1,026,304和1,018,544个人。我们使用回归不连续性来评估BCG疫苗接种对COVID-19相关结果的影响。在如此庞大的人群中使用的这种方法允许使用经典的随机对照试验很难实现高精度。 COVID-19病例和相关住院的优势比分别为0.9997（CI95：[0.8002-1.1992]）和1.1931（CI95：[0.7558-1.6304]）。因此，我们可以以95 \％的信心拒绝，普遍BCG疫苗接种将病例数减少了20％以上，并且住院数量降低了24％以上。尽管必须评估最近的疫苗接种作用，但我们提供了有力的证据，表明出生时接受BCG疫苗没有针对Covid-19的保护作用。
The Bacille Calmette-Guérin (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 Bacillus Calmette-Guérin (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. 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. 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%. 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.
