Background: During the COVID-19 pandemic children and young people (CYP) mortality in England reduced to the lowest on record, but it is unclear if the mechanisms which facilitated a reduction in mortality had a longer lasting impact, and what impact the pandemic, and its social restrictions, have had on deaths with longer latencies (e.g., malignancies). The aim of this analysis was to quantify the relative rate, and causes, of childhood deaths in England, before, during, and after national lockdowns for COVID-19 and its social changes. Methods and findings: Deaths of all children (occurring before their 18th birthday) occurring from April 2019 until March 2023 in England were identified. Data were collated by the National Child Mortality Database. Study population size and the underlying population profile was derived from 2021 Office of National Statistics census data Mortality for each analysis year was calculated per 1,000,000 person years. Poisson regression was used to test for an overall trend across the time period and tested if trends differed between April 2019 to March 2021 (Period 1)) and April 2021 to March 2023 (Period 2: after lockdown restrictions). This was then repeated for each category of death and demographic group. Twelve thousand eight hundred twenty-eight deaths were included in the analysis. Around 59.4% of deaths occurred under 1 year of age, 57.0% were male, and 63.9% were of white ethnicity. Mortality rate (per 1,000,000 CYP per year) dropped from 274.2 (95% CI 264.8–283.8) in 2019−2020, to 242.2 (95% CI 233.4–251.2) in 2020−2021, increasing to 296.1 (95% CI 286.3–306.1) in 2022−2023. Overall, death rate reduced across Period 1 (Incidence rate ratio (IRR) 0.96 (95% CI 0.92–0.99)) and then increased across Period 2 (IRR 1.12 (95% CI 1.08–1.16)), and this pattern was also seen for death by Infection and Underlying Disease. In contrast, rate of death after Intrapartum events increased across the first period, followed by a decrease in rate in the second (Period 1 IRR 1.15 (95% CI 1.00–1.34)) versus Period 2 (IRR 0.78 (95% CI 0.68–0.91), pdifference = 0.004). Rates of death from preterm birth, trauma and sudden unexpected deaths in infancy and childhood (SUDIC), increased across the entire 4-year-study period (preterm birth, IRR 1.03 (95% CI 1.00–1.07); trauma IRR 1.12 (95% CI 1.06–1.20); SUDIC IRR 1.09 (95% CI 1.04–1.13)), and there was no change in the rate of death from Malignancy (IRR 1.01 (95% CI 0.95–1.06)). Repeating the analysis, split by child characteristics, suggested that mortality initially dropped and subsequently rose for children between 1 and 4 years old (Period 1 RR 0.85 (95% CI 0.76–0.94) versus Period 2 IRR 1.31 (95% CI 1.19–1.43), pdifference < 0.001. For Asian, black and Other ethnic groups, we observed increased rates of deaths in the period 2021−2023, and a significant change in trajectory of death rates between Periods 1 and 2 (Asian (Period 1 IRR 0.93 (95% CI 0.86–1.01) versus Period 2 IRR 1.28 (95% CI 1.18–1.38), pdifference < 0.001); black (Period 1 IRR 0.97 (95% CI 0.85–1.10) versus Period 2 IRR 1.27 (95% CI 1.14–1.42), pdifference = 0.012); Other (Period 1 IRR 0.84 (95% CI 0.68–1.04) versus Period 2 IRR 1.45 (95% CI 1.20–1.75), pdifference = 0.003). Similar results were observed in CYP in the most deprived areas (Period 1 IRR 0.95 (95% CI 0.89–1.01) versus Period 2 IRR 1.18 (95% CI 1.12–1.25), pdifference < 0.001). There was no change in the trajectory of death rates for children from white (p = 0.601) or mixed (p = 0.823) ethnic backgrounds, or those in the least deprived areas (p = 0.832), between Periods 1 and 2; with evidence of a rise across the whole study period for children from white backgrounds (IRR 1.05 (95% CI 1.03–1.07), p < 0.001) and those in the least deprived areas (IRR 1.06 (95% CI 1.01–1.10), p < 0.001). Limitations include that the population at risk was estimated at a mid-point of the study, and changes may have biased our estimates. In particular, absolute rates should be interpreted with caution. In addition, child death in England is rare, which may further limit interpretation; particularly in the stratified analyses. Conclusions: In this study, overall child mortality in England after the national lockdowns was higher than before them. We observed different temporal profiles across the different causes of death, with reassuring trends in deaths from Intrapartum deaths after lockdowns were lifted. However, for all other causes of death, rates are either static, or increasing. In addition, the relative rate of dying for children from non-white backgrounds, compared to white children, is now higher than before or during the lockdowns. Author summary: Why was this study done?: We know that, during the national lockdowns initiated due to the COVID-19 pandemic, the number of children dying in England was lower than seen prior to the pandemic. The reduction in deaths appeared to be across most age groups, regions and areas of England, and in both boys and girls. The number of deaths increased once England returned to pre-pandemic rules, but we don't know what happened to the rate of death after this, and if rate of death varied according to child characteristics such as age, sex and ethnicity. What did the researchers do and find?: We identified all those children in England who died between April 2019 and March 2023 and calculated what the rate of death was for each year, for each group of children (e.g., infants or older children) and what they appeared to die of. Using a mathematical model we then tested if the rate of death was going up or down across the 4 years, and if the trend seen was different for the first two years (before and during the national lockdowns) compared to the second two (after the national lockdowns). Overall, children were less likely to die during the pandemic (April 2020–March 2021) than at any other time, with 377 fewer deaths than expected from the previous year. The number of deaths in the following year was similar to before the pandemic, but in 2022−2023, there were 258 more deaths than expected from the pre-pandemic period. While mortality in the most deprived areas, and in children of non-white ethnicities, did not drop during the pandemic, they demonstrated significant increases in the post-lockdown period, making the relative rate of dying for children from non-white backgrounds, compared to white children, higher than before or during the pandemic. What do these findings mean?: Overall, child mortality after the national lockdowns was higher than during, or preceding them. While deaths in most categories appear to have increased or remained the same, intrapartum Deaths appeared to increase during the national lockdowns, but then reduced afterwards. As the number of children in the population is based on census data, this work may not perfectly reflect the actual number of children in England and so the absolute rates of death have some uncertainty around them. Equally, the category of death (e.g., infection) is often based on early information and might change as more information is known through the Child Death Review process. David Odd and colleagues analyse rates and causes of childhood deaths in England before, during, and after the COVID pandemic, and assess temporal trends for categories of death and demographic groups. [ABSTRACT FROM AUTHOR]