Only 40% of seropositive people have neutralising antibodies

And tocilizumab can be considered to treat children and adolescents needing oxygen support for COVID-19.

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Welcome to The Medical Republic’s COVID Catch-Up.

It’s the day’s COVID-19 news in one convenient post. Email bianca@biancanogrady.com with any tips, comments or feedback.

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19 March

• A serosurvey of Wuhan residents finds nearly 7% test positive but less than half have neutralising antibodies.
• Tocilizumab can be used in adolescents and children with COVID-19 needing oxygen support.
• Latest COVID-19 infection numbers from around Australia.

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More than one person in 14 in Wuhan, China carries antibodies against SARS-CoV-2 but only 40% of those have neutralising antibodies against the virus, a study has found.
A paper published in the Lancet describes the results of a cross-sectional serological survey of nearly 3600 randomly-sampled households – representing just over 9500 individuals – across the city, which found 6.92% were positive for SARS-CoV-2 antibodies.
Four-fifths of these reported having no previous symptoms of the disease, which translated to a rate of asymptomatic infection of just under 6%.
However the authors commented that as the participants were asked to self-report symptoms, there was a likelihood of recall bias which may explain the higher rate of asymptomatic infection compared to other studies.
More women than men had antibodies, and the rates of seropositivity were lowest in those aged 12-17 years.
The study found that around half the households had two or three members who tested positive, and the seropositivity rate among families was higher in larger families.
Researchers also noted that only 39.8% of those who tested positive had neutralising antibodies, but that these antibodies were present even at nine months after exposure.

The monoclonal antibody tocilizumab – more commonly used to treat rheumatoid arthritis – can be considered as a treatment for COVID-19 in children and adolescents who need supplemental oxygen and who have evidence of systemic inflammation.
The latest update from Australia’s National COVID-19 Clinical Evidence Taskforce made the conditional recommendation because of evidence suggesting the drug reduces the risk of death in adults with severe COVID-19.
However they pointed out there was no established dose for tocilizumab for the treatment of acute COVID-19 in young people, and suggested administering it as a single intravenous infusion over one hour.
The update also featured an updated list of treatments that should not be used to treat COVID-19 outside the context of an approved clinical trial, which included ivermectin plus doxycycline, zinc, nitazoxanide, and anakinra (calm down, Star Wars fans).

Here are the latest COVID-19 infection numbers from around Australia:
National – 29,166 with 909 deaths
ACT – 123 (0)
NSW – 5251 (3)
NT – 106 (0)
QLD – 1402 (8)
SA – 640 (1)
TAS – 234 (0)
VIC – 20,483 (0)
WA – 927 (0)