US could have avoided over 53,000 coronavirus deaths if lockdown was imposed two weeks earlier: Study
The findings underscore the importance of early intervention and aggressive response in controlling the Covid-19 pandemic
Had the US implemented social distancing measures two weeks earlier, on March 1 instead of March 16, the country would have reduced the number of deaths by an estimated 53,990. This is according to a new Columbia University model that demonstrates how early action might have curtailed the growth of the virus and saved many Americans. The study highlights the dramatic effect that early, coordinated interventions have on the Covid-19 pandemic.
The Trump administration issued guidelines on March 16, asking all Americans to avoid social gatherings and groups of more than 10 people. The guidelines urged older Americans to stay home and advised people to limit gatherings to 10 or less not just in bars and restaurants but also at home. Individual states subsequently started lockdown measures. The findings are based on infectious disease modeling that analyzes how reduced contact between people starting in mid-March slowed transmission of Covid-19. The researchers modeled what would have happened if those same changes had taken place one or two weeks earlier and estimated the spread of infections and deaths until May 3.
The analysis shows that close to 36,000 deaths could have been avoided had the US entered lockdown or taken up stay-at-home measures a week earlier in March, and close to 54,000 if controls were in place two weeks earlier. Specifically, nationwide, 61.6% of reported infections and 55% of reported deaths as of May 3 could have been avoided if the same control measures had been implemented just one week earlier. Measures two weeks earlier would have reduced cases by 84% and deaths by 82.7%.
“The simulations indicate that had observed control measures been adopted one week earlier, the US would have avoided 703,975 (ranging between 624,923-773,388) confirmed cases and 35,927 (30,088-40,638) deaths nationwide as of May 3, 2020. A more pronounced control effect would have been achieved had the sequence of control measures occurred two weeks earlier: a reduction of 960,937 (900,114-1,011,498) cases and 53,990 (49,688-57,186) deaths in the US," says the study, a pre-print version of which has been published, implying that it is yet to be peer-reviewed. The findings underscore the importance of early intervention and aggressive response in controlling the Covid-19 pandemic.
"A one-week further delay to the resumption of control measures results in an average of 214,545 additional confirmed cases and 23,110 deaths nationally by July 1. In addition, the highest daily numbers of cases and deaths rise from 35,288 (19,623-52,391) and 3,392 (1,858-4,885) for the two-week response delay, to 42,560 (21,834-61,405) and 4,166 (2,150- 5,814) for the three-week response delay," the findings state. In the New York metropolitan area, 209,987 confirmed cases and 17,514 deaths would have been avoided if measures were applied one week earlier. Similarly, measures two weeks earlier could have prevented 246,082 infections and 20,427 deaths among New Yorkers.
The model experiments also indicate that rapid detection of increasing case numbers and fast re-implementation of control measures is needed to control a rebound of outbreaks of Covid-19. "Efforts to further raise public awareness of the ongoing high transmissibility and explosive growth potential of Covid-19 are still needed at this critical time. Our results also indicate that without sufficient broader testing and contact tracing capacity, the long lag between infection acquisition and case confirmation masks the rebound and exponential growth of COVID-19 until it is well underway," warns the team.
Other studies too have made similar observations. In one study, researchers project that if the US had acted earlier by implementing lockdown and stay-at-home measures, the country would have seen substantial reductions in the total number of infected cases and deaths by about 80% and 75% respectively, according to a new analysis by Chinese and US researchers. The study by researchers from Iowa State University, US; Peking University, China, and Sichuan University, China, evaluated the effectiveness of Covid-19 control strategies of countries that have experienced over four weeks of community infections.
The researchers say that March 13 and March 20 represented the dates of firm policy measures by the US and the UK governments respectively, when the US declared the national emergency and the UK started to close schools and public facilities. The researchers examined how many cases and deaths could have been avoided if measures were implemented five days earlier — March 8 for the US and March 15 for the UK. “Our result shows that by acting earlier both countries would see substantial reductions in the total number of infected cases and deaths: the US would see the cases and the deaths reduced by about 80% and 75% respectively, and the UK by 40% and 29% respectively. In contrast, under the five-day delayed postulations, the US would see the cases and deaths increase by 71% and 53%, and the UK by 61% and 40%, respectively,” says the pre-print analysis.
Another research attempted to estimate how many Covid-19 cases could have been prevented in the US when compared with the US’s actual number of cases, assuming that on a certain date, the US took China-like or South Korea-like interventions and that these interventions would have been as effective in the US as in China and South Korea. “We found that if that date was at the early stage of the outbreak (March 10), more than 99% (1.15 million) fewer infected cases could be expected by the end of the epidemic. This number decreases to 66.03% and 73.06% fewer infected cases with the China-like scenario and the South Korea-like scenario, respectively, if actions were taken on April 1, highlighting the need to respond quickly and effectively to fight the virus,” the team concludes.
Over 1,577,280 Covid-19 cases have been reported from the US as of May 22, and more than 94,700 have died in the coronavirus pandemic, according to the Johns Hopkins tracker.
Control efforts must be constantly refined: CDC
An assessment done by the US Centers for Disease Control and Prevention (CDC) shows that various gatherings of people from different locations, followed by a return to their home communities, played a notable role in the early US spread of Covid-19. It says multiple factors contributed to accelerated spread during February-March 2020, including continued travel-associated importations, large gatherings, introductions into high-risk workplaces and densely populated areas, and cryptic transmission resulting from limited testing and asymptomatic and presymptomatic spread.
"During February 2020, the number of confirmed cases originating in the US was low and appeared contained; thus, federal and local jurisdictions did not recommend restrictions on gatherings. However, during the last week of February, several large events led to further spread of the disease," says the May 1 report. "These included Mardi Gras celebrations in Louisiana with more than 1 million attendees, an international professional conference held in Boston, Massachusetts, with approximately 175 attendees, and a funeral in Albany, Georgia, with more than 100 attendees. In the weeks after these events, amplification in the host locations contributed to increasing US case counts," it says.
The substantial transmissibility of the virus and severity of Covid-19 triggered a series of recommendations, beginning in mid-March, to limit mass gatherings and travel, says experts. “During a three-week period in late February to early March, the number of US Covid-19 cases increased more than 1,000-fold. Various community mitigation interventions were implemented with the aim of reducing further spread and controlling the impact on health care capacity,” says Anne Schuchat, CDC COVID-19 response team, in the analysis.
The study says control efforts must be continuously refined as the pandemic evolves. Certain interventions that were critical in the early stages, such as quarantine and airport screening, might have less impact when the transmission is widespread in the community, it adds. “However, many elements of the mitigation strategies used during the acceleration phase will still be needed in the later stages of the outbreak. Sustained and concerted efforts will be needed to prevent future spread of SARS-CoV-2 within the US,” the expert recommends.