COVID-19 Infectious Diseases Underestimated from the Sea to the Shining Sea

The seroprevalence of SARS-CoV-2 infections varied across the country in early spring, with an estimated 1% in San Francisco up to 1% in New York City, according to CDC researchers discovered in an ongoing study by CDC researchers. Was almost 7%.

A serologic survey of approximately 16,000 people at 10 different sites in the United States estimated that infections ranged 6 to 24 times more than reported cases of COVID-19 based on antibodies to the SARS-CoV-2 spike protein, and It shows that symptomatic spread can play a significant role, with a role in CDC reported by Dr. Fiona Havers of Medicine at CDC and colleagues.

In fact, the researchers estimate that seven of these 10 sites had more than 10 times the reported cases of infection. JAMA Internal Medicine.. CDC also Interactive public dashboard With data from 10 sites that the institution said to be updated regularly.

Editorial attached to JAMA According to Tyler Brown (MD) and Rochelle Walensky (MD) of the Massachusetts General Hospital in Boston, the study is a “significant breakthrough” and a “significant reference point” for future serological investigations. .. Earlier serological studies were “focused on a cohort of areas that were narrow in scope and acquired by a specific geographical catchment or an unlimited “walk-up” registry,” they said.

In contrast, the new CDC analysis utilized blood samples collected for routine medical purposes such as cholesterol screening and inpatient monitoring.

Brown and Walensky mentioned the relevant points at which this data came up in the light of public health debates. We will start by clarifying the idea of ​​COVID-19’s “herd immunity” at this point. Editors believe that herd immune thresholds are generally considered to be between 60% and 70%, and as of mid-May, 7 out of 10 new cases were “significant, yet controlled.” Are not experiencing “increase”.

“This study condemns the idea that the current widespread adaptive immunity of the population (so-called herd immunity) poses a substantial impediment to the continued spread of SARS-CoV-2 in the United States.” They wrote.

The editors also confiscated the importance of the data in the light of increasing evidence that “acquired immunity may be short-lived” in people with mild or asymptomatic infections.

“Importantly, anything that could result in positive serogroup-level protection may be less durable than initially expected,” Brown and Warrensky said.

surely, Letter issued on Tuesday In New England Medical Journal, Researchers at the University of California, Los Angeles, reported serological results in 34 patients who were previously mostly mild to COVID-19. They found that antibody titers decreased substantially over 90 days with an average half-life of 73 days.

With two time lags between March 23 and May 12, Havers and colleagues conducted a cross-sectional study of approximately 16,000 serum samples collected for routine assays at two commercial laboratories. I did it. Samples were from 10 regions: West Washington, New York City, metropolis Philadelphia, Minneapolis, South Florida, San Francisco Bay Area, Louisiana, Missouri, Utah.

Of these specimens, 55% were female and the largest proportion (36%) was from adults age 65 and older, but there was no site-wide association between age- and gender-specific prevalence. The authors state.

Although the serum prevalence was dramatically higher than the number of cases reported in all 10 regions, the difference between the two estimates varied. The smallest was Connecticut (176,012 infections vs 29,287 cases) and the largest was Missouri (161,936 infections vs 6,794 cases).

Data limits included that the specimen was collected for clinical purposes and anonymized, and included “minimal ancillary data” about the individual collected. He noted that in areas such as New York, samples may have been taken from people seeking treatment for suspected COVID-19 symptoms at the time of the outbreak.

Brown and Warrensky emphasized that these results symbolize the flaws of testing in the country. “They have an active surveillance strategy to deploy extensive PCR or antigen-based testing to identify viruses that are replicative (clinically apparent and asymptomatic) to slow the epidemic trajectory. It is urgently needed.”

They estimated that the United States would increase PCR-based testing capacity by almost 18 times and test approximately 4.3 million people daily to effectively control the transmission of additional diseases.

Last updated: 21 July 2020