Omicron reinfection rate higher than for other variants

4 minute read

Communicable Disease COVID-19 Live blog

By

Bianca Nogrady

And NSW workers fail in appeal against employment vaccine mandates.

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

It’s the latest covid-19 news in one convenient post. Email bianca@biancanogrady.com with tips, comments or suggestions.

9 December

Omicron appears better than other variants at evading pre-existing immunity due to previous infection, according to a non-peer-reviewed preprint study from South Africa.
Researchers used epidemiological surveillance data from 35,670 suspected covid reinfections among nearly 2.8 million people with laboratory-confirmed SARS-CoV-2 between March 2020 and November 2021, to compare the rates of reinfection over that time.
However they noted that the vaccination rate in South Africa was so low – and the study did not have access to vaccination data – that it was not possible to draw conclusions about the effectiveness of vaccines against Omicron.
According to a paper published on MedRxiv, they saw that the rate of reinfections through the first three waves of the pandemic in South Africa gradually decreased, as would be expected if the risk of reinfection remained low.
The ratio of reinfection hazard to primary infection hazard declined gradually from 0.15 in the first wave to 0.12 in the second wave and 0.09 in the third wave.
“Based on these analyses, we conclude there was no population-level evidence of immune escape associated with emergence of the Beta or Delta variants,” the authors wrote.
However since Omicron emerged in early November, the ratio of reinfection hazard to primary infection hazard increased significantly to 0.25.
“Quantifying the extent of Omicron’s immune escape for both natural and vaccine-derived immunity, as well as its transmissibility relative to other variants and impact on disease severity are urgent priorities to inform facility readiness planning and other public health operations,” they wrote.

A group of workers in NSW – including an aged care worker – have failed again in their legal challenge to mandatory vaccines as a condition of employment.
According to the ABC, the case was an appeal against an October court ruling that backed the NSW government requirement that police, health and aged care workers, school staff and constructive workers be double-vaccinated.
In rejecting the appeal, the judge commented that, contrary to the argument that the vaccine mandate infringed on workers’ “bodily integrity”, the public health orders did not authorise anyone to be involuntarily vaccinated, and people could still choose not to be vaccinated.

Convalescent plasma does not improve survival nor reduce the need for ventilation, and should not be used to treat covid patients, the World Health Organisation says.
In a statement, WHO hammered the final nail in the coffin of the treatment, whose fortunes have waned dramatically since early promising results in the first months of the pandemic.
The “strong recommendation” against convalescent plasma was based on data from 16 trials involving more than 16,000 patients from across the spectrum of covid severity. It also took into consideration the logistical challenges associated with convalescent plasma, including the identification and testing of potential donors, collection and storage of plasma.

Suicide rates in Australia declined slightly during 2020 compared to the previous year, but use of emergency services for mental health crises and suicide ideation increased significantly.
The rate of suicide in Australia in 2020 was 12.1 per 100,000 people in 2020, compared to 12.9 per 100,000 in 2019, according to a report by the Australian Institute of Health and Welfare. Around 3% of the suicides recorded in 2020 had the pandemic mentioned in either the police or coroner’s report, although in most cases this was in addition to other risk factors for suicide.
However Victorian ambulance services reported an 11% increase in attendances related to suicidal ideation in 2020 compared to 2019, with the increase most noticeable in the second half of 2020. There was also a 16% increase in the number of mental health attendances in 2020 compared to 2019.
Nationally, there was a substantial increase in the number of contacts made to crisis and support organisations and in the use of mental health services.

The covid vaccine rollout continues to roll on, with 88.5% of Australians aged 16 and over now double-vaccinated:

Here are the latest covid infection numbers from around Australia to 9pm Wednesday:
National – 222,261 with 2072 deaths
ACT – 2175 (8)
NSW – 83,967 (395)
NT – 299 (1)
QLD – 2157 (2)
SA – 976 (1)
TAS – 240 (0)
VIC – 131,325 (1296)
WA – 1122 (0)

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