Australian health authorities say another three cases of rare blood clots – including in an 80-year-old Victorian man – are very likely linked to the AstraZeneca vaccine.
The medicines regulator on Friday night said the suspected cases of thrombosis with thrombocytopenia syndrome (TTS) were in a 35-year-old New South Wales woman, a 49-year-old Queensland man and the 80-year-old.
Symptom onset ranged from nine to 26 days after vaccination with AstraZeneca, the Therapeutic Goods Administration said in a statement. The Vaccine Safety Investigation Group “concluded all three of the cases were likely linked to vaccination”.
“All three patients are clinically stable, have responded well to treatment and are recovering,” the TGA said.
“Two of the three cases appear to be milder forms of the syndrome that were recognised very early by the treating health professionals and are responding well to treatment, and in one of the cases platelet counts were depressed to a limited extent and the patient developed symptoms unusually late.”
There have now been six cases of TTS in Australia linked to the AstraZeneca jab including one death.
Five of the cases were in people aged under 50 who were vaccinated prior to the government announcing on 8 April that Pfizer was the preferred vaccine for Australians under 50.
So far, there have been 1.1m doses of AstraZeneca vaccine administered in Australia.
The TGA said the majority of blood clotting cases in Australia and internationally had been in people aged under 50 years.
“The risk for TTS appears lower in older adults,” the regulator said. “While there have been some cases seen in this group, this also reflects that many countries are currently only using the AstraZeneca vaccine in older age groups. The risk of serious harm from infection with Covid-19 remains much higher in over 50s and the benefits of Covid-19 vaccination outweigh the risks.”
The TGA said while the safety investigation group had concluded the most recent three cases were “very likely linked to vaccination” further follow-up of some remaining details and some imaging and blood test results were “still being completed”.
Prof Julie Leask, a social scientist whose research focuses on infectious diseases and immunisation communication, said the official advice had not changed since early April.
“There are risks associated with having any vaccine, including the AstraZeneca vaccine,” she told Guardian Australia.
That risk doesn’t go away altogether when people turn 50, but it is lower. Australians should acknowledge that and weigh it up against the risk of contracting Covid-19, Leask said.
“We’re not just thinking here about the risk of Covid disease because we’re a country with very low transmission or almost no community-based transmission,” she said.
“We’re thinking about things to do with how we travel, how we interact with our loved ones, how concerned we might feel for them if we pass it on. The [Perth lockdown] news today is a reminder of the risks of Covid. The risks of Covid are not just health risks – there are also social and economic risks we face as a country.”