How deadly is Covid-19? Deaths in NYC during early months of outbreak resemble 1918 flu pandemic, say experts
The 1918 flu pandemic is considered to be deadliest in recorded human history, claiming the lives of an estimated 50 million people worldwide, including 675,000 people in the US. Many have questioned how deadly the coronavirus pandemic is and according to researchers, death rates during the initial phase resemble those of the 1918 Spanish flu.
Deaths from Covid-19 in New York City during the first two months of the pandemic are comparable to those seen in the city at the peak of the 1918 flu pandemic, says a team from Brigham and Women’s Hospital and Harvard Medical School. However, when improvements in hygiene, modern medicine and public health are taken into consideration, the increase in deaths in New York City during the initial period of the Covid-19 outbreak was “substantially greater” than during the peak of the 1918 pandemic, write authors. “If insufficiently treated, SARS-CoV-2 (the virus that causes Covid-19) infection may have comparable or greater mortality than 1918 H1N1 influenza virus infection,” the team warns in the study published in JAMA Network Open. It also includes experts from Yale New Haven Hospital, Emory University School of Medicine and Rollins School of Public Health of Emory University.
The researchers compared excess deaths in New York City during the peak of the 1918 H1N1 influenza pandemic and the early Covid-19 outbreak in 2020 using public data from the Centers for Disease Control and Prevention (1914-1918), the New York City Department of Health and Mental Hygiene (2020) and the US Census Bureau (2017-2020). They compared figures from March 11 through May 11 of this year — the first 61 days of the Covid-19 outbreak in New York City — to the worst 61 days of the 1918 pandemic in the city.
The analysis reveals that during the peak of the 1918 H1N1 influenza outbreak in New York City, a total of 31,589 “all-cause deaths” occurred among 5,500,000 residents. This amounts to an incident rate of 287.17 deaths per 100,000 person-months. Person-months is a standard way of measuring the number of deaths in a population during a specific period. “The incident rate ratio for all-cause mortality during the H1N1 influenza pandemic compared with corresponding periods from 1914 to 1917 was 2.80,” says the team.
During the early period of the coronavirus outbreak in New York City, 33,465 all-cause deaths occurred among 8,280,000 residents, yielding an incident rate of 202.08 deaths per 100,000 person-months. The incident rate ratio for all-cause mortality during the study period of 2020 compared with corresponding periods from 2017 through 2019 was 4.15. The incident rate ratio for all-cause mortality during the peak of the 1918 H1N1 influenza pandemic and the early 2020 Covid-19 outbreak was 0.70. According to the authors, these findings suggest that deaths associated with Covid-19 during the early phase of the New York City outbreak were comparable to the peak mortality observed during the 1918 H1N1 influenza pandemic.
“This cohort study found that the absolute increase in deaths over baseline (that is, excess mortality) observed during the peak of 1918 H1N1 influenza pandemic was higher than but comparable to that observed during the first two months of the Covid-19 outbreak in New York City. However, because baseline mortality rates from 2017 to 2019 were less than half that observed from 1914 to 1917 (owing to improvements in hygiene and achievements in medicine, public health, and safety), the relative increase during early Covid-19 period was substantially greater than during the peak of the 1918 H1N1 influenza pandemic,” the authors conclude.
According to the researchers, recent polling indicates that a majority of individuals in the US believe that some states lifted Covid-19 restrictions too quickly. Specifically, shutdowns did not adequately lower caseloads in many areas, meaning that subsequent spikes in new cases during the summer stretched US hospital resources in many areas, they emphasize. “We believe that our findings may help officials and the public contextualize the unusual magnitude of the Covid-19 pandemic, leading to more prudent policies that may help to decrease transmission by decreasing the effective reproduction number of Covid-19 and prevent the exhaustion of essential supplies of life-saving resources in the coming weeks and beyond,” says the team.