COVID-19 Update: Antibodies Decrease,
UV Light Fights Virus

Jake Remaly

July 23, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Here are the coronavirus stories Medscape's editors around the globe think you need to know about today:

Antibodies Drop Rapidly

Antibody levels in patients with mild COVID-19, the level of disease most people have, appear to drop by half within 36 days, new research suggests.

The results, published online in a letter to the editor of The New England Journal of Medicine, "put firm numbers on the dropping of antibodies after early infection," study author Otto Yang, MD, professor of medicine at the University of California, Los Angeles, told Medscape Medical News.

The rapidity in the antibody drop at 5 weeks "is striking compared to other infections," he said.

Although interpreting the data comes with a few caveats, the study indicates that there is "no reason for anybody to be getting an antibody test medically right now," Yang said.

Using UV Light to Fight Disease Spread

A century-old approach to fending off infectious diseases involves the use of ultraviolet light — known as germicidal UV — delivered in the right dose to wipe out viruses, bacteria, and other microorganisms. "Although it's not perfect, it probably offers the best solution for direct air disinfection" in the current pandemic, David Sliney, a faculty member at Johns Hopkins University and longtime researcher on germicidal UV, told Kaiser Health News.

Research shows close to 90% of airborne particles from a previous coronavirus (SARS-CoV-1) can be inactivated in about 16 seconds when exposed to a certain strength of UV. Other viruses, such as the adenovirus, require a higher dose of UV.

UV can go only so far toward preventing infection, however. People can still get sick from the larger, heavier droplets ejected via coughs and sneezes, for instance.

COVID-19 Spread Outpacing Testing Capacity

The coronavirus may be spreading faster in the United States than labs can test for it.

That, in turn, leads to a slower turnaround time for results, which can hinder contact tracing efforts. States frustrated by private laboratories’ increasingly long turnarounds for COVID-19 test results are scrambling to find ways to salvage their testing programs, Kaiser Health News reports.

One company, LabCorp, is processing about 165,000 COVID-19 tests per day, compared with 20,000 per day in late March, and averaging between 3 to 5 days to return results to someone not in the hospital.

"We're continuing to increase capacity every single week," Adam Schechter, the CEO of LabCorp, said on CNBC's Closing Bell. “The problem is that the number of tests being asked to be performed each week is growing faster than the capacity that we can build.”

A turnaround time of 2 to 3 days is necessary to effectively track and trace contacts and inform people that they may have been exposed to the coronavirus.

To that end, the National Institutes of Health (NIH) aim to facilitate COVID-19 testing that will cover 2% of the US population, some 6 million people each day, by December. That testing rate would be eight to 10 times higher than the current daily rate, NIH Director Francis Collins, MD, and colleagues write in an article published online in the New England Journal of Medicine.

CDC: Infection Rates Likely Higher Than Reported

Between late March and mid-May, it's probable that up to 10 times more coronavirus infections occurred than the number of cases that have been reported, according to a new study by the Centers for Disease Control and Prevention's COVID-19 Response Team.

Investigators studied blood samples from more than 16,000 people in 10 locations: San Francisco, Connecticut, south Florida, Louisiana, Minneapolis-St. Paul-St. Cloud, Missouri, New York City, Philadelphia, Utah, and western Washington. They estimated that the number of infections ranged from 6 to 24 times the number of reported cases.

"It is likely that greater than 10 times more SARS-CoV-2 infections occurred than the number of reported COVID-19 cases; most persons in each site, however, likely had no detectable SARS-CoV-2 antibodies," the authors reported in JAMA Internal Medicine.

No Virus Found in Injured Kidneys of Patients

Although acute kidney injury is seen in a substantial minority of patients with severe COVID-19, no evidence of the presence of SARS-CoV-2 was found in kidney biopsies from a small series of such patients, according to researchers.

"Kidney injury occurs in more than one third of hospitalized COVID-19 patients, and various catalysts have been postulated," Purva Sharma, MD, told Reuters Health News . "Our kidney biopsy research shows that the kidney injury from COVID-19 virus happens due to complications of the disease and is not because of direct viral infection of the kidney."

Sharma, of the Zucker School of Medicine at Hofstra/Northwell, Great Neck, New York, and colleagues biopsied kidneys of 10 patients (mean age, 65) with clinical features of acute kidney injury. Most had a history of type 2 diabetes or hypertension or both.

"Direct viral infection is not the main cause of acute kidney injury in our patients with active COVID-19," the researchers reported in the Journal of the American Society of Nephrology.

Don't Expect First Vaccinations Until 2021

Researchers are making "good progress" in developing vaccines against COVID-19, with a handful in phase 3 trials, but their first use cannot be expected until early 2021, a World Health Organization expert said.

WHO is working to ensure fair vaccine distribution, but in the meantime it is key to suppress the virus' spread, said Mike Ryan, head of WHO's emergencies program.

"Realistically it is going to be the first part of next year before we start seeing people getting vaccinated," he said during a public event on social media.

In Memoriam

As frontline healthcare workers care for patients with COVID-19, they commit themselves to difficult, draining work and also put themselves at risk for infection. More than 1800 throughout the world have died.

Medscape has published a memorial list to commemorate them. We will continue updating this list as, sadly, needed. Please help us ensure this list is complete by submitting names with an age, profession or specialty, and location through this form.

If you would like to share any other experiences, stories, or concerns related to the pandemic, please join the conversation here.

Jake Remaly is a staff journalist at Medscape Medical News and MDedge. He has covered healthcare and medicine for more than 5 years. He can be reached at

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