Scream in a box to avoid nasal Covid swab tests

UNCOMFORTABLE nasal and throat swabs to check for Covid have become one of the defining features of the pandemic.

But a Dutch inventor has created a more enjoyable alternative — the scream box.

The walk-in booth is based on the fact that when we scream, sing or breathe, we release tens of thousands of particles into the air, which carry the coronavirus.

By processing these particles through an industrial air filtering machine and measuring the size of them, Peter van Wees says he can identify who is infected. This is due to the distinct size of Covid particles, which measure between 0.1 and 0.5 microns, 30 times smaller than a grain of pollen.

To carry out the new test, participants step inside an airlocked cabin and scream or sing for ten seconds. The air then passes through the filtering system into another chamber, where it is dried to remove water, and put through the sizing device.

The results from the sizing device are available in a minute, says Peter Van Wees, 55, an entrepreneur with a background in mechanical engineering. He is working with a private company to gather data to prove this approach works.

Both air filtering machines and particle measuring devices are established technologies used to check for fumes and pollution.

While the filtering machine collects the sample, the sizing device, which is the size of a basketball, uses an electrical charge to remove particles from the air.

Van Wees had the idea after noting the issues with Covid swab tests.

Results of lateral flow tests — which check for antigens (proteins) that identify the virus — vary depending on who performs them. They are carried out by taking a sample from both nostrils, which is then dipped in a solution and dripped on to a device to give results in 30 minutes.

A Public Health England evaluation of one brand found its ability to identify a true positive was almost 80 per cent when done by a laboratory scientist, but 57 per cent when done by track and trace staff.

Yet new Government analysis on March 10 showed that for every 1,000 lateral flow tests carried out, there is less than one false positive result.

After making the booth, Van Wees started testing it last October.

The idea has some scientific merit, says Dr Andrew Preston, a reader in microbial pathogenesis at Bath University. ‘Using air purifiers to sample environments for surveillance of infectious particles is valid,’ he says. But it’s unclear how the virus ‘might be distinguished from others’.

There are also worries about how the booth would be cleaned. But Van Wees says the air is sucked out and an ultraviolet light will ‘demolish any virus’.

While the box is not yet approved, the £130,000 price tag might make it unlikely the scream booths will replace swabs.

However, it offers a fun alternative to testing.

As one of the volunteers, Soraya Assoud, 25, said: ‘It’s nice to scream, when nobody can hear you.’