key: cord-330692-rqwkkfp0
authors: He, Daihai; Shi, Zhao; Li, Yingke; Cao, Peihua; Gao, Daozhou; Lou, Yijun; Yang, Lin
title: Comparing COVID-19 and the 1918–19 influenza pandemics in United Kingdom
date: 2020-06-26
journal: Int J Infect Dis
DOI: 10.1016/j.ijid.2020.06.075
sha: 
doc_id: 330692
cord_uid: rqwkkfp0

Abstract We compare the COVID-19 pandemic and 1918-19 influenza pandemic in United Kingdom. We found that the on-going COVID-19 wave of infection matched the major wave of the 1918-19 influenza pandemic surprisingly well, both reached similar magnitude (in term of estimated weekly new infections) and spent the same duration above 5 cases per 1000 inhabitants, for the past two months. We discussed the similar characteristics between these two pandemics.

The fast spread and high fatality of the coronavirus disease 2019 (COVID-19) remind us of the first pandemic in last century, the 1918-19 influenza pandemic. Indeed, the SARS-CoV-2 and the 1918 A/H1N1 influenza viruses share some common properties.

 Similar basic reproductive number (R0), ranging from 2 to 4;

 Similar patterns of viral shedding from infectious patients1 ,2 thus presumably comparable generation intervals; Zou et al (2020) reported "Our analysis suggested that the viral nucleic acid shedding pattern of patients infected with SARS-CoV-2 resembles that of patients with influenza and appears different from that seen in patients infected with SARS-CoV". In particular, COVID-19 may have a similar latent period as that of influenza;

 Comparable dispersion parameter k 3, which controls the variance of the distribution of number of secondary cases caused by a typical primary case. Smaller k implies bigger contribution in the total infections from super-spreaders. For instance, 1918 influenza A/H1N1 has a relatively large k (0.94)4 compared with severe acute respiratory syndrome (SARS, 0.16) and Middle-east respiratory syndrome (MERS, 0.26). It was found that that k for COVID-19 may be 0. 8 We used the age grouped P&I data and we assume a maximum age of 80. A comparison between the YLLs for COVID-19 and 1918-19 influenza should be conducted, because YLL is the other important indicator of the severity of a pandemic.

There are many reasons to compare the current pandemic and the 1918-19 pandemic. We attempted such a preliminary comparison in Figure 2 . However, this 'match' is artificial since we choose 5% reporting ratio without strong support. We choose to match the ongoing COVID-19 to the fall wave in 1918 due that the summer wave was very minor and obviously not comparable. The population size was 44 million in 1918 and are 59 million in 2020 in E&W. If we assume a 0.5% IFR for COVID-19 in 2020 and a 2% infection fatality rate in 1918, we may calculate and compare the infections based on reported deaths which should be more reliable than reported cases. In Figure   2b , we showed such a comparison, the 'match' is unexpected. Here the 0.5% IFR for COVID-19 is a reasonable guess based on serological study in German Gangelt8 and observed infection fatality rate in Hong Kong9 and Singapore10 where testing was extensive. Furthermore, according to Faust and del Rio 11, the CFR on the Diamond Princess Cruise outbreak was 0.5% after age standardization. The two matched surprisingly well between week 7 and 16, and above 5 cases per 1000 inhabitants. Years of Life lost due to pneumonia and influenza between 1911 and 1921 in London, UK

SARS-CoV-2 viral load in upper respiratory specimens of infected patients

Virological assessment of hospitalized patients with COVID-2019

Superspreading and the effect of individual variation on disease emergence

Influenza transmission in households during the 1918 pandemic

Clustering and superspreading potential of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in Hong Kong

Mechanistic modelling of the three waves of the 1918 influenza pandemic

Prioritization of influenza pandemic vaccination to minimize years of life lost

Assessment of Deaths From COVID-19 and From Seasonal Influenza

Reconstruction of Transmission Pairs for novel Coronavirus Disease 2019 (COVID-19) in mainland China: Estimation of Super-spreading Events, Serial Interval, and Hazard of Infection

The effect of public health measures on the 1918 influenza pandemic in US cities

Inferring the causes of the three waves of the 1918 influenza pandemic in England and Wales

Acknowledgements DH thanks Jonathan Dushoff, Lewi Stone and David Earn for insightful discussion. We thank International Infectious Disease Data Archive (IIDDA) for influenza data.