Abstract：
Public health systems reported low mortality from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in East Asia, in low-income countries, and for children during the first year of the SARS-CoV-2 pandemic. These reports led commentators to suggest that cross-reactive immunity from prior exposure to other pathogens reduced fatality risk. Resolution of initial infection waves also contributed to speculation that herd immunity prevented further waves prior to vaccination. Serology instead implied that immunity was too limited to achieve herd immunity and that there was little impact from cross-reactive protection. Paediatric deaths exceeded those from influenza, with higher age-specific fatality risk in lower-income nations and similar fatality risk in East Asia compared with demographically similar regions. Neither pre-outbreak exposure to related pathogens nor immunity induced by initial infection waves are necessarily a reliable response to future pathogen outbreaks. Preparedness for future pathogen outbreaks should instead focus on strategies such as voluntary behavioural changes, nonpharmaceutical interventions, and vaccination.
摘要：
公共卫生系统报告说，东亚严重急性呼吸道综合症冠状病毒2（SARS-CoV-2）的死亡率很低，在低收入国家，以及SARS-CoV-2大流行第一年的儿童。这些报告使评论员提出，先前暴露于其他病原体的交叉反应性免疫力降低了死亡风险。初始感染波的消退也有助于推测群体免疫在接种疫苗之前阻止了进一步的波。血清学反而暗示免疫太有限，无法实现群体免疫，交叉反应保护几乎没有影响。儿科死亡人数超过流感死亡人数，与人口相似地区相比，低收入国家的特定年龄死亡风险较高，东亚的死亡风险相似。爆发前暴露于相关病原体或由初始感染波引起的免疫都不一定是对未来病原体爆发的可靠反应。相反，对未来病原体暴发的准备应侧重于诸如自愿行为改变之类的策略，非药物干预措施，和疫苗接种。
