And 'long COVID' affects more than half of those hospitalised with the disease.
Welcome to The Medical Republicâs COVID Catch-Up.
Itâs the dayâs COVID-19 news in one convenient post. Email bianca@biancanogrady.com with any tips, comments or feedback.
17 March
- New data suggests AstraZeneca vaccine has low efficacy against South African variant.
- Long COVID affects more than half of those hospitalised with the disease.
- Australian immunisation authority says no evidence of increased clot risk with AstraZeneca vaccine.
- Actual prevalence of COVID-19 in United States may be more than double the number of known cases.
- Latest COVID-19 infection numbers from around Australia.
The latest clinical trial of the AstraZeneca/Oxford COVID-19 vaccineâs effectiveness against the South African variant has further muddied the waters.
A study, published in the New England Journal of Medicine, randomised 2026 HIV-negative individuals to either the two-dose ChAdOx1 nCoV-19 vaccine â which uses a viral vector carrying a component of the SARS-CoV-2 spike protein â or placebo, with a primary endpoint being prevention of confirmed, symptomatic COVID-19.
While the vaccine was found to generate strong neutralising antibody responses, the study saw little difference between the two groups in the rate of mild to moderate COVID-19 infection, representing a vaccine efficacy of just 22%.
The majority of infections were caused by the B.1.351 South African variant, which is defined by a collection of mutations in the gene coding for the SARS-CoV-2 spike protein.
However, there were no cases of severe disease in either the vaccine or placebo groups, which the authors described as an inconclusive result with respect to the vaccineâs effectiveness at preventing severe disease.
âDeliberations on the utility of the ChAdOx1 nCoV-19 vaccine also need to be made in the context of ongoing global spread and community transmission of the B.1.351 variant and the evolution of other SARS-CoV-2 lineages that include similar mutations,â the authors wrote.
The majority of individuals experiencing âlong COVIDâ say the condition is affecting their family life and their ability to work.
The UKâs National Institute for Health Research surveyed a self-selected population of 3286 individuals with long COVID â persistent symptoms following SARS-CoV-2 infection that can include post-intensive care syndrome, post-viral fatigue syndrome, and even permanent organ damage.
More than one-third said the condition was affecting their finances, and 80% said it affected their ability to work.
The NIHR also conducted a review of research into long COVID, which found that 20%-30% of those not admitted to hospital were still experiencing at least one symptom more than a month after diagnosis, and one in 10 had at least one persistent symptom three months later. Among those admitted to hospital, 50%-89% had at least one symptom persisting at two months.
Women and children are over-represented among those presenting with long COVID, relative to the numbers who experience COVID-19 overall.
Many of those surveyed felt they hadnât been able to access the healthcare services they needed. The reviewâs authors commented that the significant health burden that long COVID presented may require new delivery models for health services.
The evidence to date on clotting incidents associated with the AstraZeneca/Oxford COVID-19 vaccine does not support a suspension of its use in Australia, says the Australian Technical Advisory Group on Immunisation.
In a statement, ATAGI said it had reviewed evidence in light of more European countries halting vaccinations, and found that the overall rate of thrombotic events in vaccine recipients was no higher than what would be expected in the general population.
The group also cited data from the UKâs Medicines and Healthcare Products Regulatory Agency, which has noted no safety signals despite more than 11 million doses of the vaccine being administered so far in the UK.
No clotting events have been reported in Australia in association with the vaccine, but the Therapeutic Goods Administration is monitoring the situation.
The actual prevalence of SARS-CoV-2 infection in the United States may be double that of recorded figures, new research suggests.
A study published in JAMA Network Open reported the results of a national sample of nearly 62,000 self-reported healthy individuals applying for life insurance across the United States, who were also tested for antibodies to SARS-CoV-2.
Overall 6.6% tested positive â slightly more women than men â and seropositivity rates ranged from 9.8% in those under 30 years to 2.8% in those aged over 70 years.
The authors extrapolated from this representative sample that nearly 16 million cases of COVID-19 had gone undiagnosed in the United States as of September 2020.
Here are the latest COVID-19 infection numbers from around Australia to 9pm Tuesday:
National â 29,137 with 909 deaths
ACT â 123 (0)
NSW â 5242 (2)
NT â 105 (0)
QLD â 1388 (2)
SA â 636 (2)
TAS â 234 (0)
VIC â 20,483 (0)
WA â 926 (1)
