Despite three doses already doing little to prevent the surge of Omicron BA.4 and BA.5, two of the most infectious Covid subvariants yet, a fourth jab is available to anyone over 30 to avoid severe infection.Federal Health Minister Mark Butler told Melbourne radio 3AW that the government is ready “with more than enough vaccine in the warehouses and more than enough capacity in our pharmacies in our GP surgeries to deliver that as soon as people want it,” he said.Here’s what the world can teach Australia about the fourth-dose:Does the WHO recommend a fourth-shot?No. While countries have begun offering a fourth jab (and fifth for immunocompromised), it is not officially recommended by the World Health Organisation.“Data on the usefulness of these additional booster doses is sparse and especially limited on the duration of further protection,” the WHO said in a statement.The data that does exist has only been studied for the mRNA vaccines from Pfizer and Moderna, with not detail available for jabs from AstraZeneca and others.What country was first with four doses?Israel was the first country to offer a fourth jab when it began rolling out the second booster course in January this year.The shot was offered to adults aged over 18-years, and more than 830,000 Israelis took up the offer.Most were elderly, immunocompromised, and health workers.After Israel, countries began offering a fourth shot to elderly and immunocompromised despite the lack of formal recommendations from health authorities.They include Britain, France, Germany, Sweden, Chile, Denmark, Hungary, Cambodia, Thailand, South Korea and Singapore.Is a fourth shot effective?Seven studies have been conducted on a fourth dose, six of which were from Israel and one from Canada, and all during a time when Omicron has been the predominant circulating strain.A study published in the New England Journal of Medicine in April found the effects of a fourth shot was no different to a third shot among regular person’s immune response.Among elderly Israeli’s, however, a more recent study found the fourth dose found protection against infection among those aged over 60 and living in aged-care homes.Researchers from the epidemiology and preventive department at Tel Aviv University compared the 24,088 fourth-dose recipients to 19,687 who received only three doses four months prior.The fourth shot was associated with 34 per cent protection against infection, and 64 to 67 per cent against acute hospitalisation for mild-to-moderate and severe illness, plus 72 per cent against deaths.But, they added, protection against infection with an Omicron variant was “modest” at best.“Taken together, these studies show some short-term benefit of an additional booster dose of mRNA vaccine in health workers, those over 60 years of age or with immunocompromising conditions,” the WHO said in a statement.“Data to support an additional dose for healthy younger populations are limited; preliminary data suggest that in younger people, the benefit is minimal.”NED-6507-Covid-Booster-GuideDid the fourth shot prevent the spread of Covid?While Israel is the most highly vaccinated country in the world, and the first to offer a fourth shot, it continued to suffer waves of virus surges.The country recorded more than 70,000 infections in the past week, according to Johns Hopkins University.A study found that despite continued circulation in the country, and that protection of a fourth shot appeared short lived, there were fewer reported rates among those with a fourth shot compared to those with three.“Rates of confirmed SARS-CoV-2 infection and severe Covid-19 were lower after a fourth dose of BNT162b2 vaccine than after only three doses,” the study concluded.What are the vaccine makers saying?Despite inconclusive data, no official recommendation from health authorities, and no discernible effect in stopping the spread of Covid, the vaccine manufacturers are nonetheless pushing for fourth doses immediately.Pfizer CEO Albert Bourla said in an interview a fourth dose was “necessary”, and added they are submitting data to the Food and Drug Administration on its importance.“Right now, the way that we have seen, it is necessary, a fourth booster right now. The protection that you are getting from the third, it is good enough, actually quite good for hospitalisation and deaths. It’s not that good against infections,”Moderna CEO Stephane Bancel, meanwhile, said the ineffectiveness of boosters over time meant a fourth dose would be needed.“I will be surprised when we get that data in the coming weeks that it’s holding nicely over time — I would expect that it’s not going to hold great,” Bancel said in January, in reference to booster shots.“I still believe we’re going to need boosters in the fall of ‘22 and forward,” he added.justintips
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