Abstract

We thank Leo Lam and Taylor Nichols for their response1 to our paper ‘COVID-19 vaccine boosters for young adults: a risk–benefit assessment and ethical analysis of mandate policies at universities’.2 In our paper, we demonstrate that the risk–benefit calculus to mandate boosters for young adults aged 18–29 is a net risk intervention. The authors assert that we have made three inappropriate comparisons of benefits versus risks of the mRNA vaccine booster dose in this age group. We provide our response to each below. We erred on the side of overestimating benefits of the booster dose against severe COVID-19 in this age group and still found net harms to outweigh net benefits. The conclusion of our paper holds, and university booster mandates for young people were—and remain—unethical. For the first comparison, we weighed predicted hospitalisations prevented by one booster dose of BNT162b2 with vaccine-associated SAEs from the manufacturer’s randomised trial (3/5055).3 We found that the rate of expected SAEs would outweigh the benefits of the booster against hospitalisation by at least 18-fold. Lam and Nichols suggest that this was an inappropriate comparison, as not all SAEs result in hospitalisation. However, the definition of SAE as used in the trial included death, hospitalisation, disability, permanent damage, life-threatening event or condition, which required medical or surgical intervention to prevent a serious outcome.4 While all comparisons include some degree of incommensurability, comparing these SAEs with hospitalisations prevented by the booster is more reasonable than Lam and Nichols’ suggestion of comparing SAEs to infections prevented. The COVID-19 infection hospitalisation risk in this age group was <0.5% (or <1/200)5 even prior to widespread immunity, thus comparing SAEs to infection risk is entirely inappropriate. Furthermore, a booster dose will only offer transient (if any) protection against infection6 and cumulative infection rates …