There is a semantic error in the description of the ratio of TCID50 to expected infections or SIN in the text, where the ratio is described as being 1 over its correct value.

Throughout the article, the number of infections that 1 TCID50 is expected to cause has been incorrectly reported as either being 1.44 infections in theory or 1.781 infections when estimated via Reed-Muench (RM) or Spearman-Karber (SK) method. It should be the inverse of those quantities such that 1 TCID50 is expected to cause 0.6931 infection in theory or 0.5615 infection when estimated via the RM or SK method.

All occurrences of the numbers -1/ln(50%) = 1.44 and eɣ = 1.781 in the text should be replaced by -ln(50%) = 0.6931 and e-ɣ = 0.5615, respectively. There is a single exception to this on page 6 where the re-computed ratios are correctly expressed as “(RM/1.781)/SIN” and “(SK/1.781)/SIN”.

Additionally, in the Discussion, the statement:

“While, in theory, the intended MOI can be obtained by multiplying the TCID50 by 0.7 (or rather ln(2) = 0.693), one should instead multiply by 0.561 to account for the overestimation of the TCID50 by RM and SK.”

Should read:

“While, in theory, the intended MOI can be obtained by inoculating with 1.44 TCID50 (-1/ln(50%)) to infect one cell, in reality 1.781 TCID50 estimated via the RM or SK method is required to infect one cell, to account for the method’s overestimation of the TCID50.”

This semantic error was confined to the text of the article. None of the analysis, conclusions, publicly available code, or web calculator are affected.