Household Contact Is the Top Transmission Risk. And More Science Journal News

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.

Household contact is the greatest risk for transmission

Researchers in China traced more than 3,400 contacts of 391 cases of COVID-19 and found that household contacts were the most likely to be infected, with a secondary infection rate of about 10 per cent. The risk of infection for close contacts in other situations was lower, at about four per cent, and transmission on public transportation was rare. Patients with more severe disease were more likely to infect their close contacts than those with less severe disease, and asymptomatic cases were the least likely to infect their close contacts.

Annals of Internal Medicine, Aug. 13, 2020

RNA vaccine shows promise in early trials

An RNA vaccine candidate called BNT162b1 shows promise based on interim results from a combined Phase 1 and Phase 2 clinical trial. The vaccine induced a robust immune response, with only mild or moderate side effects in some participants, including pain at the injection site, fatigue, headache, fever and sleep disturbance. RNA vaccines work by giving the body a genetic blueprint for one of the virus’s important proteins, which cells use to create antibodies. A larger Phase 3 trial will be needed to test the vaccine’s efficacy before it can be approved for widespread use.

Nature, Aug. 12, 2020

The first wave infected few children

Children made up a small proportion of confirmed COVID-19 cases in England during the pandemic’s first wave, despite large numbers being tested. Just four per cent of the more than 35,000 tests carried out on children between January and May this year were positive, compared with a rate of between 19 and 35 per cent for adults. Children also had a much lower death rate than adults. The researchers say the results confirm that children likely aren’t an important source of COVID-19 infection, but warn that the study period included a long period of lockdown when there was less opportunity for exposure to the virus.

Archives of Disease in Childhood, Aug. 12, 2020

In Texas, the age of second-wave patients dropped

Between the first and second wave of the pandemic, the age of patients lowered significantly in Texas after the state reopened. The average age of hospitalised patients in the Houston Methodist hospital system during the second wave — from May 16 to July 7 — fell by more than two years, from 59.9 to 57.3. The hospitals also saw a significant increase in Latino patients, and those from lower socioeconomic backgrounds.

JAMA, Aug. 13, 2020

No herd immunity in Sweden

Sweden’s controversial policy of allowing controlled spread of COVID-19 in the population seems to have failed to deliver on the goal of herd immunity. The country did not impose a strict lockdown like most countries in Europe, and as a result had higher rates of infection, hospitalisation and mortality compared with neighbouring countries. The health authority predicted that 40 per cent of the Stockholm population would have had the disease and acquired antibodies by May 2020. In reality, only 15 per cent had.

Journal of the Royal Society of Medicine, Aug. 11, 2020

Clinical trials lack diversity

Minority groups are significantly underrepresented in many COVID-19 clinical trials, despite having disproportionately higher rates of infection, hospitalisation and death from the virus. In a trial of the drug remdesivir conducted by Gilead, the company behind the drug, just 10 per cent of the study participants were Black, and less than one per cent were Latino or Indigenous. A government-funded trial did better, with 20 per cent Black participants, and 23 per cent Latino or Indigenous. Researchers warn that without representative populations in trials, it will be difficult to generalize the results to the population at large.

New England Journal of Medicine, Aug. 11, 2020

Excess deaths were comparable to 1918

The absolute increase in deaths over baseline — more mortality than normal — observed during the peak of the 1918 H1N1 influenza pandemic was higher than, but comparable to, that observed during the first two months of the COVID-19 outbreak in New York City. But because there were fewer baseline deaths — less mortality overall compared with 1918 due to general improvements in hygiene and health care — mortality was greater in New York City during COVID-19 than during the 1918 flu pandemic.

JAMA Network Open, Aug. 13, 2020

COVID-19 was spreading earlier than thought

COVID-19 was spreading much earlier than thought in Wuhan, China, and Seattle, Wash., according to a reanalysis of throat swabs from people with flu symptoms before the pandemic was fully recognized. The re-tested swabs revealed that around two-thirds of infections were from the flu virus, but around one-third of them were COVID-19, suggesting the virus was circulating for weeks before each city went into lockdown. In the United States, about one-third of the estimated undiagnosed cases were in children, and the first case in Seattle may have arrived as early as Christmas 2019, well before the first confirmed case on Jan. 21.

EClinicalMedicine, Aug. 12, 2020

Convalescent plasma safe and effective

A preliminary analysis from an ongoing study of more than 300 COVID-19 patients treated with convalescent plasma — blood from people who have recovered from the virus — has found that the treatment is safe and effective. Those treated early in their illness with donated plasma that has the highest concentration of anti-COVID-19 antibodies are more likely to survive and recover than similar patients who were not treated with convalescent plasma.

American Journal of Pathology, Aug. 10, 2020

Alarming rise in domestic violence

There has been a dramatic increase in injuries associated with domestic violence during the COVID-19 lockdown. Researchers at Brigham and Women’s Hospital in Boston identified more incidents of abuse during the spring of 2020 than in each of the previous three years, as well as a higher proportion of severe cases, suggesting that victims reached out for health-care services in later stages of abuse due to fear of COVID-19.

Radiology, Aug. 13, 2020