key: cord-0983145-ekzf4gl2
authors: Grech, Victor; Scherb, Hagen
title: COVID-19: Mathematical estimation of delay to deaths in relation to upsurges
date: 2020-10-01
journal: Early Hum Dev
DOI: 10.1016/j.earlhumdev.2020.105210
sha: 0f5b744a6f9337bbd79710531fa45d3c72e72e68
doc_id: 983145
cord_uid: ekzf4gl2

Introduction The world continues in the grip of the COVID-19 pandemic. Widespread public health measures and travel restrictions have dampened viral spread but outbreaks are expected as restrictions are raised. This study was carried out in order to devise an approach that may help to predict deaths based on upsurges (spikes or waves) of cases. Methods Publically available data for daily new cases and deaths from December 2019 to August 2020 was obtained from the Our World In Data website. For the purposes of more detailed analysis, in addition to total global data, three countries were chosen for sub analysis: Italy, Germany and the United States. Results Delay to death (days) were as follows: World: 20.6 (95% CI: 8.4-32.8); USA: 19.8 (95% CI: 9.3-30.4); Germany: 18.8 (95% CI: 6.1-31.6); Italy: 2.4 (95% CI -10.2-15.0). Discussion Countries may be able to contain viral resurgence by adhering to WHO advice for reopening from restrictions/lockdowns. However, outbreaks are almost inevitable and deaths are to be expected approximately 20 days after rises in cases. This paper may therefore aid healthcare systems and hospitals for surges in cases as positive COVID-19 swabs increase in any given locality.

The world is stricken by the COVID-19 pandemic that was initially identified in Wuhan, China, in December 2019, a virus that circulates widely before resulting in severe infections that produce hospital admissions and deaths.(1,2) COVID-19 precipitated international travel bans in March 2020 so as to slow down and dampen viral spread, and this affected over 90% of the world's population. (3) This, accompanied by public health measures, may have delayed millions of infections and prevented the deaths of millions more. (4, 5) While COVID-19 is a beta coronavirus and not an influenza virus, its transmission characteristics are similar to influenza and it is expected to resurge after being dampened in a series of waves as restrictions are relaxed and reapplied. (6) These successive wave/s have length/s and amplitude/s that are determined by herd immunity and the stringency of applied lockdowns. (7) This paper will utilise publicly available national datasets of COVID-19 detections by swabbing, and deaths in order to attempt to devise an approach that may help to predict deaths based on upsurges (spikes or waves) of cases. 

Publically available data for daily new cases and deaths from December 2019 to August 2020 was obtained from the Our World In Data website.(8) Data is available for swab confirmed cases and this is an inherent limitation in any such study as:

1. It is estimated that there are many asymptomatic or mild cases that are undocumented. (9) 2. Some cases may never be documented even if death ensues due to the absence of sufficient testing capacity as is common in developing countries (and even some developed countries such as the United States. For the purposes of more detailed analysis, in addition to total global data, three countries were chosen for sub analysis. These were Italy due to this country being the first disease epicentre outside of China, and Germany and the United States as two countries that represent effective and ineffective population disease control respectively. 

For the period 1 st January 1 to 10 th August 2020, the data shows 731,263 worldwide daily deaths and 19,845,092 Covid-19 cases (symptomatic and asymptomatic).

Counts of daily deaths, cases, Covid-19 tests performed, as well as the corresponding positive rate are shown in Table 1 . The standardized cross correlation employed for point and 95%confidence interval estimation of the optimum time delay between the daily deaths and the daily positive rate are shown in Table 2 . Figure 1 

The world is in the second wave of COVID-19 and in the absence of an effective vaccine and/or effective treatment, resurgences are expected to further take tolls on COVID-19 morbidity, mortality and affected countries' economies. (12) Overall, it appears that spikes or upsurges in cases are followed by deaths approximately 20 days 

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