SARS-CoV-2

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Can you sanitize the inside of your nose to prevent COVID? Nope, FDA says.

doesn’t pass the sniff test —

There are a lot of COVID nasal sprays for sale, but little data to show they work.

Can you sanitize the inside of your nose to prevent COVID? Nope, FDA says.

More than four years after SARS-CoV-2 made its global debut, the US Food and Drug Administration is still working to clear out the bogus and unproven products that flooded the market, claiming to prevent, treat, and cure COVID-19.

The latest example is an alcohol-based sanitizer meant to be smeared inside the nostrils. According to its maker, the rub can protect you from becoming infected with SARS-CoV-2 and other nasty germs, like MRSA, and that protection lasts up to 12 hours after each swabbing. That all sounds great, but according to the FDA, none of it is proven. In a warning letter released Tuesday, the agency determined the sanitizer, called Nozin, is an unapproved new drug and misbranded.

While ethyl alcohol is used in common topical antiseptics, like hand sanitizers, the FDA does not generally consider it safe for inside the nostrils—and the agency is unaware of any high-quality clinical data showing the Nozin is safe, let alone effective. The FDA also noted that, for general over-the-counter topical antiseptics, calling out specific pathogens it can fight off—like SARS-CoV-2 and MRSA—is not allowed under agency rules without further FDA review. Making claims about protection duration is also not allowed.

The FDA’s warning letter is nothing to sneeze at; the letter threatens seizure and injunction for failing to adequately respond.

Nozin’s maker, Maryland-based Global Life Technologies Corp., did not immediately respond to a request for comment from Ars. On its website, the company touts its product’s effectiveness with a link to a published study from 2014, indicating that use of Nozin lowered the colonization levels of S. aureus and other bacteria in the noses of 20 healthy health care workers. The study did not address protection from infection or carriage of any viruses. The company also lists unpublished studies indicating that the product can kill bacteria in laboratory conditions, does not irritate skin, and lowered bacterial growth in the noses of 30 people over a 12-hour period.

This is far from the first dubious, nasal-based COVID product the FDA has called out. There was the Corona-cure nasal spray of 2020, and the Halodine and the NanoBio Protect nasal antiseptics of 2021. That year, the Federal Trade Commission sued a company called Xlear over allegedly false claims that its nasal spray can prevent and treat COVID-19. At least two more nasal spray makers received FDA warning letters in 2022.

To date, the FDA has not approved any nasal sprays to prevent or treat COVID-19, and the scant data on their efficacy remains inconclusive. But there are still plenty of such products for sale online. Most, like Nozin, claim to work by killing bacteria and viruses directly. One product, a nitric oxide nasal spray called Sanotize, is currently in a Phase III clinical trial to test whether it can prevent SARS-CoV-2 infections. Others claim to work by coating the nasal passage with the gelling agent iota-carrageenan to provide a barrier to viral entry. A pilot clinical trial of 400 health care workers in Argentina published in 2021 found that the use of an iota-carrageenan nasal spray led to a 4 percent absolute risk reduction in SARS-CoV-2 infection.

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Contact-tracing software could accurately gauge COVID-19 risk

As it turns out, epidemiology works —

Time spent with infected individuals is a key determinant of risk.

A woman wearing a face mask and checking her phone.

It’s summer 2021. You rent a house in the countryside with a bunch of friends for someone’s birthday. The weather’s gorgeous that weekend, so mostly you’re all outside—pool, firepit, hammock, etc.—but you do all sleep in the same house. And then on Tuesday, you get an alert on your phone that you’ve been exposed to SARS-CoV-2, the virus that causes COVID-19. How likely are you to now have it?

To answer that question, a group of statisticians, data scientists, computer scientists, and epidemiologists in the UK analyzed 7 million people who were notified that they were exposed to COVID-19 by the NHS COVID-19 app in England and Wales between April 2021 and February 2022. They wanted to know if—and how—these app notifications correlated to actual disease transmission. Analyses like this can help ensure that an app designed for the next pathogen could retain efficacy while minimizing social and economic burdens. And it can tell us more about the dynamics of SARS-CoV-2 transmission.

Over 20 million quarantine requests

The NHS COVID-19 app was active on 13 to 18 million smartphones per day in 2021. It used Bluetooth signals to estimate the proximity between those smartphones while maintaining privacy and then alerted people who spent 15 minutes or more at a distance of 2 meters or less from a confirmed case. This led to over 20 million such alerts, each of which came with a request to quarantine—quite a burden.

The researchers found that the app did, in fact, accurately translate the duration and proximity of a COVID-19 exposure to a relevant epidemiological risk score. The app assessed a contact’s risk by multiplying the length of contact, the proximity of contact, and the infectiousness of the index case as determined by how long it had been since the index case started showing symptoms or tested positive.

There was an increasing probability of reported infection as the app’s risk score increased: more contacts whom the app deemed were at a high transmission risk did go on to test positive for COVID-19 within the following two weeks than those who were notified but had lower risk levels. (That’s positive tests that were reported by using the app. Some of the high-risk people probably did not test at all, did not report their test results, or did not report them within the allotted time. So this is an underestimation of the correlation between notification of risk and infection.)

More exposure = higher risk

When the researchers separated the factors contributing to the risk of an exposure, they found that duration was the most important indicator. Household exposures accounted for 6 percent of all contacts but 41 percent of transmissions.

One caveat: The app didn’t record any contextual variables that are known to impact transmission risk, like if people live in an urban or rural area, was the meeting indoors or outdoors, was it during the week or over the weekend, was anyone vaccinated, etc. Including such data could make risk assessment more accurate.

Based on their work, the researchers suggest that an “Amber Alert” stage could have been introduced to the app, in which people deemed to have an interim degree of risk would be guided to get a PCR test rather than immediately jumping to quarantine. Including this intermediate Amber Alert population could have significantly reduced the socioeconomic costs of contact tracing while retaining its epidemiological impact or could have increased its effectiveness for a similar cost. Performing analyses like this early on in the next pandemic to determine how it is transmitted might minimize illness and strain on society.

Nature, 2023.  DOI:  10.1038/s41586-023-06952-2

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