COVID-19 Scan for Jul 20, 2020

Undercounted COVID deaths in Italy
Korean COVID-19 contact tracing
SARS-CoV-2 and mosquitoes

Death rate in Italy rose 104.5% during COVID-19 pandemic, analysis finds

The official COVID-19 death count from the pandemic in Italy is likely a significant undercount, according to a research letter published today in JAMA Internal Medicine.

After comparing National Health Authority coronavirus death data from Feb 23 to Apr 4, 2020, with preliminary death data from the Italian National Institute of Statistics from Jan 12 to Apr 4 in 2015 to 2019, the researchers concluded that the annual all-cause death count in March and early April 2020 rose 104.5% to 41,329, from, on average, 20,214 in previous years.

On average, from 2015 to 2019, 9,395 men and 10,819 women died each year in March and early April. But from Mar 1 to Apr 4, 2020, 21,266 men and 20,063 women died, increases of 126.4% and 85.4%, respectively.

And 5,417 people aged 65 to 74 years died from Mar 1 to Apr 4 this year, compared with, on average, 2,566, a 111.1% increase. In 2020, 32,829 people aged 74 years and older died, versus 15,677 in the previous years, a 109.4% increase.

Of the 41,329 all-cause deaths reported from Mar 1 to Apr 4, 2020, 19,824 occurred in the hard-hit northern region of Lombardy, versus 7,248 in 2019, an increase of 173.5%. Of the 19,824 deaths, 10,415 involved men (compared with 3,328 in 2019) and 9,409 involved women (compared with 3,920).

In Italy, deaths are attributed to COVID-19 only for patients who test positive in hospitals and some nursing homes, not for those who died at home or in nursing homes that didn't perform testing.

Noting that many other countries are also concerned about coronavirus death undercounts, the authors said that several factors may explain the findings, "including additional deaths directly related to the virus, deaths related to underlying health conditions exacerbated by the virus, and delayed care from the avoidance of hospitals or the demands on hospitals of caring for COVID-19 patients," they wrote. "The differences for men, for people 65 years and older, and for the Lombardy region are particularly noteworthy."
Jul 20 JAMA Intern Med research letter


South Korean study finds high coronavirus transmission in older kids

A study of contacts of South Korean coronavirus patients found that the highest rate of household transmission occurred with index patients ages 10 to 19, while the lowest was in households with younger children, researchers from the Korean Centers for Disease Control and Prevention reported last week in Emerging Infectious Diseases.

In the study, the researchers monitored 59,073 contacts of 5,706 index patients for an average of 9.9 days after SARS-CoV-2 (the virus that causes COVID-19) was detected in the index patient. Of the contacts, 10,592 were in the same household as the index patient, and 48,481 were non-household contacts. The researchers grouped the index patients by age: 0 to 9, 10 to 19, 20 to 29, 30 to 39, 40 to 49, 50 to 59, 60 to 69, 70 to 79, and 80 years and older.

A total of 11.8% (95% confidence interval [CI], 11.2% to 12.4%) of household contacts of index patients had COVID-19, compared with only 1.9% of non-household contacts. In households with index patients 10 to 19 years of age, 18.6% (95% CI, 14.0% to 24.0%) of contacts had COVID-19, which was higher than any other age group. The lowest rate of transmission was seen in households where the index patient was 0 to 9 years (5.3%; 95% CI, 1.3% to 13.7%).

The authors of the study note several limitations, including the fact that they could not determine the direction of transmission, asymptomatic cases might not have been identified, and detected cases could have been exposed outside the household. But they suggested the results of the study, which was conducted when schools were closed in South Korea, need to be considered as schools are reopened. 

"Although the detection rate for contacts of preschool-aged children was lower, young children may show higher attack rates when the school closure ends, contributing to community transmission of COVID-19," they wrote. "The role of household transmission of SARS-CoV-2 amid reopening of schools and loosening of social distancing underscores the need for a time-sensitive epidemiologic study to guide public health policy."
Jul 16 Emerg Infect Dis study


Mosquitoes unlikely to transmit SARS-CoV-2, study finds

New research by scientists from Kansas State University's College of Veterinary Medicine shows that mosquitoes are unlikely to be a vector for transmission of SARS-CoV-2, the virus that causes COVID-19, according to a study published late last week in Scientific Reports.

The scientists inoculated three common species of mosquito—Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus—with SARS-CoV-2, with the hypothesis that if the virus did not replicate in the mosquitoes under an extreme viral challenge, the lack of replication would preclude the possibility of biological transmission.

While samples collected within 2 hours of inoculation confirmed efficient delivery of the virus, no virus was detected in the 277 mosquitoes collected and titrated at any time after 24 hours, "suggesting a rapid loss of infectivity and the lack of replication after injection."

"Based upon the lack of detectable infectious virus in any of the 277 samples collected at all time points beyond 24 h post-inoculation, we conclude that SARS-CoV-2 is unable to replicate in mosquitoes and that even if a mosquito fed on a person with virus in the blood, that the mosquito would not be a vector if feeding on a naïve host," the scientists wrote.
Jul 17 Sci Rep study

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