Compiled by veteran medical journalist Brian Owens, this roundup of some of the newest science on the COVID-19 pandemic, straight from the scientific journals, is presented by Hakai Magazine in partnership with The Tyee.
Mortality was lower during second wave
Fewer people died from COVID-19 during the second wave of infections in most wealthy countries, according to a new analysis. Researchers found that in western Europe and much of the United States, the mortality rate dropped sharply after the first wave of infections — in some cases more than 10-fold.
The researchers say there could be several explanations for the change: the numbers from the first wave may be unreliable; the first wave tended to affect older people, while the second hit younger people; and doctors learned how to better treat the disease. Countries with more socialized and equitable health systems also tended to have lower mortality. But some places bucked the trend. In Belarus, as well as the U.S. states of Tennessee and Arkansas, the mortality rate actually went up slightly, though the researchers did not posit why.
Why variants spread faster
The new variants of SARS-CoV-2 that arose in the United Kingdom, South Africa and Brazil spread more quickly because of a mutation that makes their spike proteins sturdier. During infection, the spike proteins bind to a cell, then change shape to allow the virus to fuse with the cell membrane. But sometimes the proteins change shape too early, which slows infection.
All three of these variants, however, have a small mutation that makes the spikes more stable. This means more spikes are available to bind to a cell, which makes the virus more infectious. On the upside, our immune system is better at recognizing the sturdier spike on the new variant, so new versions of vaccines that target the variants may be more effective at producing protective antibodies.
AstraZeneca vaccine less effective against South African variant
The COVID-19 vaccine made by AstraZeneca is not effective at preventing mild to moderate disease among people infected with the B1351 variant first identified in South Africa. The World Health Organization, however, still recommends the vaccine be used in countries where the variant is present because it likely still protects against severe disease and death. Researchers say this work highlights the importance of developing new versions of vaccines to target this and other variants.
Vaccination alone unlikely to contain COVID-19
Fully vaccinating all adults in the United Kingdom is unlikely to achieve herd immunity and fully contain the virus, according to a new modelling study. Researchers found that even if vaccines can prevent 85 per cent of infections, there will likely be another large wave of infections after the vaccine rollout is complete if authorities remove other control measures, such as wearing masks and physical distancing. But a gradual reopening, high vaccine uptake, and a vaccine with high protection against infection, can minimize the scale of infections, hospitalizations and deaths.
Anti-Asian hashtags linked to Trump’s 'Chinese virus' tweet
The number of tweets about the coronavirus containing anti-Asian hashtags rose sharply in the week after former U.S. president Donald Trump tweeted about the “Chinese virus” — a term that public health experts warned against using. Researchers found that after Trump used the term on Twitter on March 16, 2020, users who adopted the hashtag #chinesevirus were far more likely to pair it with other overtly racist hashtags.
By contrast, those who adopted #covid19, the WHO’s official name for the disease, were far less likely to include racist hashtags in their tweets. The researchers analyzed hashtags, rather than the content of the tweets themselves, because hashtags have been shown to act as a predictor of the formation of hate groups and the occurrence of hate crimes.
The carbon footprint of protective equipment
The carbon footprint of PPE provided to health and social care staff in England during the first six months of the COVID-19 pandemic was equivalent to flying from London to New York 244 times every day, according to a new study. The three billion items of PPE used from February to July 2020 generated 591 tonnes of carbon dioxide a day, or 27,000 times the average individual’s carbon footprint. Gloves had the biggest environmental impact, followed by aprons, face shields and masks. Local manufacturing and reusing, recycling and reducing the volume used by washing hands instead of using gloves could help reduce the impact on the environment.
First cases in China were likely earlier than thought
SARS-CoV-2 was likely circulating at low levels in China’s Hubei province in early November 2019, and possibly as early as mid-October, according to a new simulation of the pandemic. The early versions of the virus may have been less dangerous, but mutated to give rise to the version that was eventually identified after it had established itself in Wuhan in late December 2019. The delay highlights the difficulty in surveillance for new pathogens with high transmissibility and moderate mortality rates.
Reinfections are rare, but more common in elderly
Most people who catch COVID-19 are protected from being infected again for at least six months, according to a study in Denmark. But people over the age of 65 are more prone to reinfection, with only a 47 per cent protection against repeat infection compared with 80 per cent for younger people. The researchers detected no evidence that protection from repeated infection waned over the six months of the study.
High levels of vitamin D may protect against COVID-19 for Black people
Having vitamin D levels above what is normally considered sufficient may lower the risk of infection with COVID-19, especially among Black people. While levels of 30 nanograms per millilitre or more are usually considered sufficient, researchers found that Black individuals who had levels of 30 to 40 ng/ml were 2.64 times more likely to test positive for COVID-19 than those with levels of 40 ng/ml or greater. No statistically significant associations of vitamin D levels with COVID-19 risk were found in white people. The researchers are now starting clinical trials to test whether vitamin D supplements can help prevent COVID-19.
Burnout and disrupted sleep linked to severe COVID-19
Insomnia, disrupted sleep and daily burnout are linked to a heightened risk of not only becoming infected with COVID-19, but also having more severe disease and a longer recovery time, according to an international survey of health-care workers. The study found that every one-hour increase in the amount of time spent asleep at night was associated with 12 per cent lower chance of becoming infected with COVID-19.
But naps didn’t help — an extra hour acquired in daytime napping was associated with a six per cent higher chance of infection. Those who reported feeling burnt out every day were more than twice as likely to be infected with COVID-19, and around three times as likely to say that their infection was severe and that they needed a longer recovery period.