Sudden Unexpected Infant Deaths: 2015-2020.

OBJECTIVE: Although the US infant mortality rate reached a record low in 2020, the sudden infant death syndrome (SIDS) rate increased from 2019. To understand if the increase was related to changing death certification practices or the coronavirus disease 2019 (COVID-19) pandemic, we examined sudden unexpected infant death (SUID) rates as a group, by cause, and by race and ethnicity. METHODS: We estimated SUID rates during 2015 to 2020 using US period-linked birth and death data. SUID included SIDS, unknown cause, and accidental suffocation and strangulation in bed. We examined changes in rates from 2019 to 2020 and assessed linear trends during prepandemic (2015-2019) using weighted least squares regression. We also assessed race and ethnicity trends and quantified COVID-19-related SUID. RESULTS: Although the SIDS rate increased significantly from 2019 to 2020 (P < .001), the overall SUID rate did not (P = .24). The increased SIDS rate followed a declining linear trend in SIDS during 2015 to 2019 (P < .001). Other SUID causes did not change significantly. Our race and ethnicity analysis showed SUID rates increased significantly for non-Hispanic Black infants from 2019 to 2020, widening the disparities between these two groups during 2017 to 2019. In 2020, <10 of the 3328 SUID had a COVID-19 code. CONCLUSIONS: Diagnositic shifting likely explained the increased SIDS rate in 2020. Why the SUID rate increased for non-Hispanic Black infants is unknown, but warrants continued monitoring. Interventions are needed to address persistent racial and ethnic disparities in SUID.

Sudden Unexpected Death in Infancy: Current Practices in Virological Investigations and Documentation in the French Registry.

OBJECTIVE: To describe pre-COVID-19 pandemic current practices in virological investigations, including type, frequency of samplings, and documented viruses, in sudden unexpected death in infancy (SUDI) and to compare results according to the cause of death. STUDY DESIGN: Between May 2015 and December 2019, infants under 2 years of age included in the French SUDI registry were classified in one of 4 groups by causes of death according to the classification by Goldstein et al. : unexplained (SIDS), infectious, explained but noninfectious, and undetermined. Sampling sites and viruses detected were described, and then SIDS and explained deaths (control group) were compared. RESULTS: Among 639 infants, 3.6% died of an established viral infection. From 23 sampling sites and 2238 samples, 19 virus species were detected. Overall, 43.3% of infants carried a virus, with no significant difference between SIDS infants and the control group (P = .06). We found wide variations in frequencies of samples by site (550 for nasopharynx to one for saliva). The highest positivity rate was from the nasopharynx (195/2238; 8.7%). Rhinovirus was the predominant virus detected (135/504; 26.8%), mostly in SIDS (83/254; 32.7%). We found no significant difference between positivity rates and distribution of viruses between the SIDS and control groups. At-autopsy virological analysis never contributed to determining the cause of death. CONCLUSION: Current practices in virological investigations in SUDI are heterogeneous, with wide variability despite published guidelines. Investigations should be limited to the most relevant sites, and systematic at-autopsy sampling should be reconsidered. We found no association between virus detection and SIDS.