In Reply to Li et al.

We thank Li et al for their comments¹ on our article “Low-Dose Whole Lung Irradiation for Treatment of COVID-19 Pneumonia: A Systematic Review and Meta-Analysis.”² The authors note important issues that we will respond to in this letter.

First, as we mentioned in the article, our search included studies that were published before February 2022; the studies noted by the authors as not having been included in our systematic review all were published after this time point. Also, the final results of the LOWRAD-Cov19 trial³ were detected during the peer review process of our manuscript and were subsequently included in the final publication.

Second, regarding the search strategy of our study, we chose the 2 most robust databases (PubMed and Scopus), and there have been no missing articles associated with COVID-19 whole lung irradiation (WLI) published until our last search date. Moreover, both MeSH and free-text terms were used for our search.

Third, all ongoing trials on the subject that were registered at clinicaltrials.gov were presented as a supplementary table. We are also very eager to find out the results of these trials so that an updated meta-analysis might bring more light to the matter after the publication of these studies.

Fourth, performing a sensitivity analysis for the overall survival rate outcome would have been futile, because it is not a comparative outcome and merely reports the rate of surviving patients who received WLI.

Fifth, considering the risk of bias, imprecision, inconsistency, indirectness, and publication bias as per grading of recommendations, assessment, development and evaluations certainty assessment requirements,⁴ the upcoming results of the ongoing trials are likely to affect the confidence in the estimates of effect for the outcomes reported in our meta-analysis, and therefore, the quality of evidence might not be higher than moderate.⁵ We clearly stated these factors within the article.

Finally, we should once again emphasize that our meta-analysis did not demonstrate a significant benefit of WLI for COVID-19 patients with moderate to severe pneumonia, and therefore, it does not support evidence for routine implementation of WLI in this population. Similar to Li et al, we believe that an updated meta-analysis after the publication of the major trials in this regard might provide new information, although it is very unlikely to change the current COVID-19 management strategies with the major vaccination programs and novel therapeutics available.