South Korea is tightening coronavirus prevention measures as the country sees record-breaking daily case rates. Although Seoul is not yet going into full lockdown, residents are not allowed to go to nightclubs or large social gatherings for at least two weeks.
They’re also not permitted to work out hard and fast at the gym. Under the new regulations, treadmills are capped at 3.7 miles per hour, and music played over the gym speakers cannot exceed 120 beats per minute.
For reference, that’s about the tempo of “Call Me Maybe” by Carly Rae Jepsen, or the BTS hit “Boy With Luv.” Both songs would set the pace for a brisk walk or a really slow jog.
But anything more strenuous than a power walk has been deemed a transmission risk. (That means gym-goers will not be able to angry run to “good 4 u” by Olivia Rodrigo or bench press to the beat of Kanye West’s “Power.”)
Under the new rules, exercisers are also required to wear masks, even if fully vaccinated, and workout class sizes are limited. While those policies could help curb the spread of COVID-19, experts are skeptical that slowing down the music will have the intended effect.
Some infectious disease experts are baffled by the new rule
“When you run faster, you spit out more respiratory droplets, so that’s why we are trying to restrict heavy cardio exercises,” Son Young-rae, spokesperson for the Ministry of Health and Welfare, said in a radio interview Monday.
But some scientists and lawmakers aren’t buying it.
Dr. Kim Woo-joo, an infectious disease specialist at Korea University Guro Hospital in Seoul, told the New York Times the gym policies were “absurd” and “ineffective.”
“So you don’t get COVID-19 if you walk slower than 6 km per hour?” said Kim Yong-tae, a member of the main opposition People Power Party, according to Reuters. “And who on earth checks the BPM of the songs when you work out? I don’t understand what COVID-19 has to do with my choice of music.”
Other experts pointed out that slowing down the music won’t necessarily discourage people from working out at a high intensity. And other prevention measures, like ensuring good ventilation and spacing out gym-goers, have already been proven effective.
No coronavirus variant spotted so far is more concerning than Delta, the strain first identified in India in February. World Health Organization officials on Monday said Delta is the “fittest” variant to date, since it spreads even more easily than other variants and may lead to more severe cases among unvaccinated people.
“Delta is a superspreader variant, the worst version of the virus we’ve seen,” Eric Topol, director of the Scripps Research Translational Institute, tweeted last week.
But it’s possible that Delta is the worst the coronavirus is going to throw at us – that the virus, in other words, has reached what epidemiologists call “peak fitness.”
Topol and Italian virologist Roberto Burioni explore that scenario in a letter published in the journal Nature on Monday. The virus, they wrote, is likely to hit a point after which it no longer mutates to become more infectious. In that case, they said, “a “‘final’ variant will prevail and become the dominant strain, experiencing only occasional, minimal variations.”
It’s too soon to know whether that’s happened, since Delta isn’t yet dominant worldwide. But it likely will be soon -Delta has been detected in more than 80 countries so far and is already dominant in India and the UK.
“Delta is absolutely going up the fitness peak – whether it’s at the top, I think that’s very hard to say until we just don’t see any further change,” Andrew Read, who studies the evolution of infectious diseases at Pennsylvania State University, told Insider.
“If Delta takes over the world and nothing changes,” he added, “then we’ll know in a while – a year or two – that it is the most fit.”
The fittest variants are the best at spreading
The coronavirus is constantly mutating in relatively harmless ways, but every once in a while, a mutation turns the virus into a more menacing threat. A new variant develops that can evade antibodies generated in response to a vaccine or prior infection, results in more serious illness, or spreads more easily.
Emerging research indicates that Delta checks at least two of those boxes.
Public Health England found that Delta is associated with a 60% increased risk of household coronavirus transmission compared to Alpha, the variant discovered in the UK. Alpha is already around 50% more transmissible than the original strain, according to the Centers for Disease Control and Prevention.
Researchers in Scotland also found that getting infected with Delta doubles the risk of hospital admission relative to Alpha. (Previous studies have suggested that Alpha may be 30% to 70% deadlier than the original strain.)
What’s more, emerging research indicates that a single vaccine dose doesn’t hold up as well against Delta as it does against other coronavirus strains. Recent Public Health England analyses found that two doses of Pfizer’s vaccine were 88% effective at preventing symptomatic COVID-19 from Delta, while a single shot was just 33% effective. That’s compared to 95% efficacy against the original strain, with 52% after one shot.
The best way for the coronavirus to achieve peak fitness, Topol and Burioni wrote in their letter, is to become more contagious. If a variant is already spreading quickly, there’s no urgent need for it to evade the body’s immune response; it can simply jump to another person.
“Increasing rate of transmission from person to person is what we’re looking for,” Read said.
That doesn’t necessarily mean the coronavirus has reached maximum transmission, though.
Read said Delta could still acquire combinations of mutations that make it even better at spreading (what he called a “Delta-plus” variant). It’s also possible that two separate variants – Delta and Alpha, for instance – could combine mutations to produce an even more infectious strain. Under a third scenario, Read said, an entirely new lineage might replace Delta as the dominant variant.
“The biggest concern at the moment is just the sheer number of people that have the virus and therefore the sheer number of variants that are being generated,” Read said. “Some of those might be the jackpot which are even fitter than Delta.”
Still, vaccines will likely provide at least some protection against whatever strain represents the coronavirus’ peak fitness.
“No human vaccine has ever been undermined by a variant to the point where the vaccine was completely useless,” Read said.
A single dose of the Pfizer or AstraZeneca COVID-19 vaccine cut the spread of coronavirus within a household by up to 50% in a new study.
People who had one dose of either vaccine were between 40% and 50% less likely to pass on the virus to people in their household, 21 days after the shot, compared to those who weren’t vaccinated at all, the study authors from Public Health England said in a preprint paper posted Wednesday.
Both vaccines – one made by Pfizer and German partner BioNTech, the other by AstraZeneca and the University of Oxford – are two-dose vaccines.
The virus is highly likely to spread from person to person within a household. PHE said it expected similar results in other high-risk settings, such as shared accommodations and prisons.
“Not only do vaccines reduce the severity of illness and prevent hundreds of deaths every day, we now see they also have an additional impact on reducing the chance of passing COVID-19 on to others,” Mary Ramsay, head of PHE, said in a statement.
The study has not yet been peer-reviewed by experts.
The researchers looked at 57,000 contacts of people who had a COVID-19 vaccine, and compared them to a group of nearly 1 million contacts for unvaccinated people.
Given the researchers looked at lab-confirmed cases only, it was not possible to conclude from the research how well vaccines stop people spreading asymptomatic COVID-19.
Dr. Peter English, a retired consultant in communicable disease control, said in a statement that the authors may have actually underestimated the vaccines’ effectiveness in preventing transmission, because the vaccinated person’s contacts could have caught COVID-19 from someone else.
“This study shows that even if people who are vaccinated do become infected, they are considerably less likely to be infectious, and to pass the infection on to others,” he said.
A UK-based study reported by Insider Thursday showed a single dose of either Pfizer or AstraZeneca’s vaccine reduced symptomatic and asymptomatic coronavirus infections overall by more than 65%.
Deborah Dunn-Walters, British Society for Immunology COVID-19 Taskforce chair and professor of immunology at the University of Surrey, said in a statement that the study was welcomed, but there was still much to learn about how COVID-19 vaccines affect transmission.
“It is still very important for us all to get two doses of the COVID vaccine to ensure we receive the optimal and longest lasting protection, both for ourselves and our communities,” she said.