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Science + Tech

It’s OK to Stretch Out a Second Vaccine Dose. And More New COVID Science

The latest roundup of pandemic findings gathered by Hakai Magazine.

Brian Owens 23 Feb 2021 | Hakai Magazine

Brian Owens is a freelance science writer and editor based in St. Stephen, New Brunswick. His work has appeared in Hakai Magazine, Nature, New Scientist, the Canadian Medical Association Journal and the Lancet.

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.

Longer intervals between vaccine doses do not reduce effectiveness

With supplies of COVID-19 vaccines low, many jurisdictions are opting to delay the second dose of two-dose vaccines to maximize the number of people who have at least partial protection from the virus. Now new research has shown that this strategy does not reduce the overall effectiveness of the vaccines, and in some cases may improve it.

A reanalysis of data on the Pfizer-BioNTech vaccine found that a single dose is 92 per cent effective after two weeks — not far off the overall 95 per cent effectiveness of the two-dose regimen. And a study of the Oxford-AstraZeneca vaccine, which is not yet approved in Canada, found that a three-month gap between doses was actually more effective than a six-week one. The World Health Organization and Health Canada have both endorsed extending the time between doses to stretch vaccine supplies further.

New England Journal of Medicine, Feb. 17, 2021

The Lancet, Feb. 19, 2021

The impact of COVID-19 on Africa has been underestimated

The lack of reliable data has contributed to a perception that Africa has been largely spared from the worst effects of COVID-19. But a new study has found that the toll is likely to be much higher than thought. Researchers tested 364 deceased people in Lusaka, Zambia, between June and September 2020 and found that COVID-19 accounted for between 15 and 20 per cent of the deaths — much higher than official reports suggest.

Most deaths in people with COVID-19 happened outside the hospital, and none had been tested for the virus before death. The deaths also occurred across a wider age spectrum than reported elsewhere and were concentrated among people under 65, including an unexpectedly high number of deaths in children.

The British Medical Journal, Feb. 17, 2021

More than 20 million years of life lost to COVID-19

The COVID-19 pandemic has led to the loss of more than 20.5 million years of life around the world, with each death being, on average, 16 years earlier than expected, according to a study of coronavirus deaths and life expectancy in 81 countries. By comparison, the years of life lost to COVID-19 is so far two to nine times greater than the loss associated with seasonal flu, and between a quarter and a half as much as the loss attributable to heart conditions.

Scientific Reports, Feb. 18, 2021

High support for lockdown, but low trust in government

People in the United Kingdom were highly supportive of putting strict controls in place to fight COVID-19 during the early phase of the pandemic, but that did not mean they trusted the government’s competence, honesty or motives. A survey of more than 9,000 people found that 95 per cent were in support of the government having powers to enforce behaviour change. However, only around half thought that the government was actually doing a good job of controlling COVID-19, and just 36 per cent thought the government “always or mostly” told the truth about the virus.

PLOS One, Feb. 16, 2021

Children’s immune systems react faster

Children may be less susceptible to severe COVID-19 because their innate immune system — the body’s first line of defence against germs — reacts more quickly to attack the virus than in adults. A study of 48 children and 70 adults exposed to COVID-19 in Melbourne, Australia, found that the children had a more robust immune response compared with the adults.

Nature Communications, Feb. 17, 2021

How many health-care workers are infected but asymptomatic?

Health-care workers are at higher risk of COVID-19 infection, but how many of them might be infectious without showing symptoms? A study at several Toronto-area hospitals found that 0.5 per cent of health-care workers — one in every 200 — tested positive for the virus despite showing no symptoms at the time of the test. Antibody blood tests reveal that between 1.4 and 3.4 per cent had been infected at some time in the past although they have never shown any symptoms.

PLOS One, Feb. 16, 2021

Pandemic prompted a surge in community values

An analysis of Google searches and social media posts in the United States has revealed a dramatic shift in attitudes and values during the pandemic. Researchers noted a sharp rise in the use of words like “help,” “share” and “sacrifice” on social media, indicating a rise in community-oriented values. There was also evidence of a focus on more basic needs like food and shelter, with a pronounced rise in searches for and mentions of things like “growing vegetables,” “sewing machine” and the one word whose usage increased the most during the pandemic: “sourdough.”

Human Behaviour and Emerging Technologies, Feb. 9, 2021

COVID-19 can cause PTSD

Around 30 per cent of people with severe COVID-19 suffer from post-traumatic stress disorder after the experience — a rate similar to that seen in previous coronavirus epidemics such as SARS in 2002. Women, people with a history of psychiatric disorders, and people who experienced delirium or agitation during their illness were at higher risk. Those with PTSD were also more likely to experience the symptoms of “long COVID” after recovering from the infection.

JAMA Psychiatry, Feb. 18, 2021

Combination of vaccines and distancing can end lockdowns

A combination of robust vaccination programs and strict physical distancing rules could avoid recurring waves of COVID-19 infections without the need for stay-at-home orders, according to computer simulations based on cities in China. The researchers found that cities with medium- and high-density populations will need both vaccination and distancing to prevent future waves of COVID-19 until herd immunity is reached. But cities with low populations and effective vaccination could fully interrupt transmission without the need for physical distancing.

Nature Human Behaviour, Feb. 18, 2021

Neanderthal gene can also protect against COVID-19

In October, we reported that a cluster of genes inherited from our Neanderthal ancestors could increase the risk of severe COVID-19. Now the same group of researchers has found that Neanderthals also contributed a gene that offers some protection from the virus. They found a region on chromosome 12 that reduces the risk of needing intensive care by 20 per cent. The genes in this region regulate the activity of an enzyme that breaks down viral genomes, and the Neanderthal variant seems to do this more efficiently. Around half of all people outside Africa have this gene variant.

Proceedings of the National Academy of Sciences, March 2, 2021  [Tyee]

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