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Science + Tech

Eviction Bans Reduced Viral Transmission. And Other Science Journal Findings

The latest roundup of pandemic findings gathered by The Tyee.

Brian Owens 20 Apr 2021 | TheTyee.ca

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.

Physical activity reduces risk of severe COVID-19

Regular physical activity, such as walking 30 minutes a day at a moderate pace, provides strong protection against hospitalization, admission to intensive care, and death among COVID-19 patients. Conversely, being consistently inactive more than doubled the risk of hospitalization and conferred the third highest risk of death from COVID-19, after old age and having had an organ transplant. Even a small amount of exercise had some benefit — those who were inconsistently active still had lower odds of severe COVID-19 than those who never exercised.

British Journal of Sports Medicine, April 13, 2021

Suicides fell in BC in early months of the pandemic

Despite fears that the stresses of the pandemic would lead to an increase in suicides, a new study has found that suicide numbers actually remained largely unchanged or even declined during the first few months of the pandemic in high or upper-middle income countries.

The study looked at suicide numbers in 21 countries between April and July 2020 and found no evidence of an increase. In many places, the numbers actually declined — British Columbia, for example, recorded 24 per cent fewer suicides in that time period than expected based on trends in previous years. But the researchers warn that the effects of the pandemic on mental health and suicide could take longer to unfold.

The Lancet Psychiatry, April 13, 2021

Researchers highlight the importance of airborne transmission

There is consistent, strong evidence that COVID-19 is predominantly transmitted by air, in small aerosols rather than larger droplets that quickly fall and contaminate surfaces, according to an assessment by a group of leading experts including the University of Toronto’s David Fisman.

They point to 10 different lines of evidence that support that conclusion, such as the fact that transmission is much more common indoors than outdoors and is greatly reduced by indoor ventilation, and that asymptomatic transmission from people who are not coughing or sneezing accounts for at least 40 per cent of all infections. The researchers urge public health authorities to reduce the emphasis on things like surface cleaning and to focus more on ways to fight airborne transmission, such as ventilation, air filtration, reducing crowding and the amount of time people spend indoors, and wearing masks whenever indoors.

The Lancet, April 15, 2021

Childhood vaccination rates declined during pandemic

The number of children receiving recommended vaccines for childhood diseases such as measles dropped dramatically at the beginning of the pandemic, according to a study of more than one million children in California. Measles vaccinations among children aged two to 18, for example, initially declined by 93 per cent before recovering somewhat, but the numbers for 2020 remained lower than in 2019. By May 2020, vaccinations in children under the age of two had recovered completely, but the gap remained more severe and persistent in older age groups.

Pediatrics, April 15, 2021

Meat-packing plants increase infection rates in the local area

Several large outbreaks of COVID-19 have been centred on meat-packing facilities, including in places like High River, Alberta and London, Ontario. Now a study of meat processing facilities in the United States has quantified how they have contributed to the pandemic. Researchers found that beef- and pork-processing plants more than doubled infection rates in the local county, while chicken-processing plants increased transmission rates by 20 per cent. They estimate that 334,000 COVID-19 cases are attributable to meat-packing plants in the U.S., resulting in US$11.2 billion in economic damage from deaths, health-care costs and lost wages.

Food Policy, April 8, 2021

Previously infected people should still get vaccinated, but they might only need one dose

A previous infection with COVID-19 does not offer complete protection against future infections, according to a new study of U.S. Marine recruits. Among the recruits who had previously been infected with COVID-19, 10 per cent of them were reinfected during basic training. By comparison, almost half of the recruits who had not been infected before developed a new infection (the high infection rate was likely due to the crowded living conditions and close personal contact common in basic training). In both groups the majority of infections were asymptomatic.

This indicates that even people who have recovered from COVID-19 should still get vaccinated to reduce their chances of reinfection. But another study has found that they may only need a single dose to get the full effect. The study found that previously infected people have a robust immune response to the first dose of an mRNA vaccine but saw little immune benefit from the second dose.

The Lancet Respiratory Medicine, April 15, 2021

Science Immunology, April 15, 2021


The effect of Israel’s vaccination campaign

Israel’s high-speed vaccination campaign, in which almost 70 per cent of the population over the age of 16 had received at least one dose within the first two months, led to a dramatic drop in infections and hospitalizations.

As of Feb. 24, cases had dropped by 77 per cent and hospitalizations had dropped by 68 per cent compared to the peak numbers seen in the pandemic. Though some of the reduction could be due to other factors, such as a one-month national lockdown in January and February, the researchers are confident that the majority of the effect was due to the protection provided by vaccines.

Nature Medicine, April 19, 2021

Eviction bans protect entire communities

Eviction bans enacted in the U.S. during the COVID-19 pandemic reduced transmission of the virus and not only protected those who would have lost their homes but entire communities from infection.

A computer model based on major U.S. cities predicts that people who are evicted or who live in a household that hosts evictees have 1.5 to 2.5 times more risk of being infected than if the eviction bans were in place. Without an eviction ban, the risk of infection also rose for the entire city, not just those directly affected by an eviction. Looking specifically at Philadelphia, the researchers estimated that, without eviction bans, there could have been approximately 5,000 more COVID-19 cases if evictions occurred at pre-pandemic levels, and up to 50,000 additional cases if evictions were five times more frequent.

Nature Communications, April 15, 2021

Vaccines are less effective in people with blood cancer

The mRNA vaccines against COVID-19 may be less effective in people with blood cancers like chronic lymphocytic leukemia and multiple myeloma, according to two new studies. The studies found that people with the two conditions had lower antibody response rates to the vaccines than healthy controls. In both cases, immune responses were lowest in people undergoing active cancer therapy, but since people with blood cancers are at high risk of complications from COVID-19, the researchers strongly recommend that they still get the vaccine.

Blood, April 16, 2021 (1)

Blood, April 16, 2021 (2)  [Tyee]

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