COVID-19 Update: Fatality Rate, Dog Detectives

Rabiya S. Tuma, PhD

July 30, 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:

Calculating Fatality Rates

While COVID-19 infections and deaths mount, researchers and clinicians are anxious to know just how deadly the new coronavirus is. But accurately calculating the risk of death is anything but easy, Perry Wilson, MD, explains in a new commentary. The case fatality rate, which measures the number of deaths among those diagnosed, is heavily dependent on how much testing is done and where in the disease course the cases are.

Perhaps more important for medical professionals though is infection fatality rate (IFR), which includes everyone infected and is measured after everyone has either recovered or died. Because it includes all outcomes, IFR highlights how good the medical system is at treating patients. Unfortunately, in the midst of the pandemic that's hard to calculate. 

Now, however, researchers — using "an impressive bit of statistical rejiggering," according to Wilson — have arrived at solid IFR estimates for different geographic regions. 

The results suggest that treatment has improved over time and that IFR differences between regions may not be as large as previously thought in terms of mortality. For patients and clinicians though, no matter how you count them, deaths are still tragic and our best strategy remains to prevent infections, Wilson cautions.

Dogs Can Identify COVID-19 Infections

After some training, dogs appear to be able to sniff out and identify people who are infected with the coronavirus, according to a new study

The researchers suspect dogs detect metabolic changes that occur in patients when they are infected. 

So far the team has trained just a handful of animals, but if the work progresses, dogs could be used to sniff out infected individuals in airports, borders, and other public places to help slow the spread of disease.

"Superspreaders" Exhale Excess Viral Particles

Many individuals infected with SARS-CoV-2 are unlikely to transmit the virus, according to a new modeling study. But some individuals, called superspreaders, can put out millions of virus particles per cubic meter of air. 

For example, whereas low emitters typically put out fewer than one viral particle per cough in a simulation experiment, high emitters — these superspreaders — put out more than 36,000 viral copies. 

Individuals with high viral loads appear more likely to be superspreaders, the researchers suggest. But duration of exposure, activities (such as singing and talking loudly), and locations (indoor vs outdoor and well-ventilated vs not) also contribute to the likelihood of spread.

CMS Announces Payment for COVID Counseling

The Centers for Medicare & Medicaid Services (CMS) announced today that physicians and other healthcare providers can be reimbursed for counseling patients about the need to self-isolate between the time of testing and symptom onset, as well as if they test positive.

Clinicians can use existing codes for reimbursement and the counseling will be covered regardless of where a patient is tested, the agency said. 

The new payment is far from the only change the pandemic has brought to the US primary care system. And if handled right, many of those changes, including an increased reliance on technology, could be lasting improvements, according to the authors of a new essay. 

Moderna Vaccine in Primates

Moderna's mRNA-1273 vaccine against SARS-CoV-2 protected rhesus monkeys from nasal and pulmonary infection in a viral challenge, according to data published this week in the New England Journal of Medicine

The vaccine, which encodes a copy of the spike protein the virus uses to enter cells, was tested at two dosages. At the higher dose, researchers found no evidence of viral replication in the nose of any of the eight animals vaccinated 2 days after the challenge. Similarly, no viral replication was detected in the lungs of seven of eight of the animals in both dose groups. 

The vaccine induced both antibody and type 1 helper T-cell responses, the researchers note. 

A phase 3 randomized trial testing the vaccine in 30,000 high-risk adult volunteers started this week as well.

Retracted Paper Linked 5G, COVID-19

A paper that one expert called the "worst paper of 2020" has been retracted. The study purportedly found a link between 5G networks and risk for COVID-19.

In communications with Retraction Watch , the journal editors came up with numerous excuses for the publication. The subsequent retraction notice on the journal website is brief but not reassuring: "This article has been retracted at the request of the Editor. After a thorough investigation the editor-in-chief has retracted this article as it showed evidence of substantial manipulation of the peer review."

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. Thousands 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.

Rabiya S. Tuma, PhD, is an executive editor with Medscape Medical News. She has covered science and medicine for a variety of publications, including The Economist and The Journal of the National Cancer Institute. She can be reached at

For more news, follow Medscape on Facebook, Twitter, Instagram, and YouTube.

Here's how to send Medscape a story tip.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.