Booster brings protection up to 97% against infection

6 minute read

And Omicron's infectious period could last longer than seven days.

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

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

17 January

A Pfizer booster dose is associated with 97%-99% effectiveness in preventing hospitalisation or death from covid, according to preliminary data from the UK during the Delta outbreak.
The research summary, published in Nature Medicine, presented data from around 893,000 individuals, 278,000 of whom were unvaccinated, 394,000 of whom had had two doses, and the remainder who had had a booster dose.
From two weeks after the booster, individuals had a 94%-97% lower risk of symptomatic disease, and protection against hospitalisation or death was as high as 99%, with no evidence of waning efficacy at 10 weeks.
“This study provides real world evidence of significant increased protection from the booster vaccine dose against mild and severe disease irrespective of the primary course,” the authors wrote.
Meanwhile, data from Chile suggests death rates from covid are 25 times higher among unvaccinated or partly vaccinated individuals than among triple-vaccinated individuals.
As of 1 January 2022, Chile was reporting 3.26 deaths per 100,000 unvaccinated or partly vaccinated people, compared to 0.13 deaths per 100,000 boosted individuals, Our World In Data reported. Even among double-vaccinated individuals, the death rates were 14 times lower than in unvaccinated individuals, at 0.23 deaths per 100,000 people in that group.

Longer telephone/video consultations are now supported by Medicare, as the government introduces an MBS item number for level C consultations that will remain in place until at least 30 June this year.
Medical groups, including the AMA, RDAA and the RACGP have all welcomed the announcement. More details from TMR’s Holly Payne here.

Around half of people infected with Omicron could still have high viral loads – a proxy for infectiousness – at day five after infection, even if they are double- or triple-vaccinated, new research suggests.
A non-peer-reviewed preprint study published by Harvard University involved 97 adults with Omicron and 107 with Delta, who were tested daily with RT-PCR after an initial positive result.
Among the 27 people with Omicron who had been undergoing daily testing before testing positive, and had a negative result the day before their positive test, 52% were still above a threshold of viral load that represented infectiousness at day five, one-quarter were above that threshold at day six, and 13% were above it by day seven after testing positive.
However the study found that the length of the proliferation phase with Omicron – from first infection to peak viral load – varied enormously, from just over one day to nearly 10 days.
Overall, those with Omicron took an average of 9.8 days to clear the virus, compared to 10.9 days for Delta, and the peak viral load was slightly lower for Omicron than Delta. All the individuals in the study were negative on RT-PCR by 15 days after the initial positive result.
Commenting on their results, the authors stressed that the high degree of variation in how long people remained infectious with Omicron meant caution was needed around potentially shortening isolation periods for those with the infection.
“Testing may be beneficial for tailoring individual decision-making and reducing the risk of premature release from isolation while also limiting unnecessarily prolonged isolation,” they wrote.

US health insurers forked out nearly US$2.5 million in reimbursements for ivermectin in one week alone last year, according to a paper in JAMA, suggesting an annual spend of nearly US$130 million.
Researchers analysed national claims data for around 6.2 million Americans and singled out oral ivermectin prescriptions dispensed during the week of 13 August 2021 to patients without continuous enrolment for ivermectin or without a diagnosis of parasitic infection in the seven days before receiving the drug.
They identified an estimated 84,400 ivermectin prescriptions that were highly likely to be for covid, and calculated that this amounted to nearly US$2.49 million-worth of spending on a treatment not supported by any clinical evidence.
“For perspective, this total exceeds estimated annual Medicare spending on unnecessary imaging for low back pain, a low-value service that has received extensive attention,” they wrote.

The Russian-made Sputnik V vaccine is now officially ‘recognised’ by the Therapeutic Goods Administration, meaning travellers who have received two doses of the vaccine are allowed entry into Australia. However the recognition doesn’t extend to the one-dose ‘Sputnik Light’.
The vaccine is still not approved by the World Health Organisation or the European Medicines Agency, despite being the first covid vaccine to be licensed anywhere in the world.

No, the federal government is not stealing your rapid antigen tests, according to the federal government.
In response to accusations that the Commonwealth is diverting orders of rapid antigen tests otherwise destined for retail sale, the federal health department has issued a statement denying it is a sneaky RAT thief.
“While we are aware there are supply constraints within the market, it is expected supply will normalise over the coming weeks,” the federal health department said in a statement.
However Australians desperate to get their hands on the test kits are falling prey to scammers and scalpers, with the Australian Competition and Consumer Commission currently receiving around 150 reports a day of price-gouging for rapid antigen tests.
In a statement, the ACCC warned that the tests were reportedly being retailed for $20-$30 and even up to $70 per test, even though the wholesale cost is between $3.95-$11.95.
Nearly half of the complaints have been made about pharmacies.

After nearly two years of reporting and charting the daily covid numbers from around Australia, we’ve decided to pause this feature of the covid blog due to the current unreliability of the federal government’s daily published data.
The federal health department’s daily tallies for states and territories do not yet include rapid antigen test-detected cases, despite the fact that many states and territories are now including those in their daily counts.
The strict limits placed on eligibility for PCR testing, and the lack of availability of rapid antigen tests, also likely mean that a significant number of positive cases are not being diagnosed or reported.
As a result, any published data is likely to massive underestimate the true number of cases, and relying on government data risks giving a false sense of security.
We will, however, continue to report the daily figure of deaths from covid. There were 35 deaths reported around Australia to 9pm Sunday, bringing the total so far in the pandemic to 2668.

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