On Tuesday, there were 356 Covid-19 patients being treated in intensive care wards throughout Australia. Of those, 25 were fully vaccinated.
While the data points to the extraordinary efficacy of Covid-19 vaccines in preventing people from becoming severely unwell, being hospitalised and dying, it does raise the question: why do a small number of people become seriously ill and, in rare cases, die, despite being fully vaccinated?
An intensive care unit staff specialist at Nepean hospital in Sydney, Dr Nhi Nguyen, said those who are fully vaccinated and die tend to have significant underlying health conditions. Being treated in intensive care, where people may be on a ventilator and unable to move, added to any existing frailty, especially in elderly people, she said.
“If we think about intensive care patients in general, whether they are there due to Covid-19, pneumonia or any other infection, we know that those who have underlying disorders, those who are frail, and those with co-morbidities will have a higher risk of dying from whatever the cause of being in intensive care is,” she said.
“Being fully vaccinated against Covid protects you from getting severe disease, yes, but it doesn’t completely protect you from getting Covid. So if you are someone with chronic health conditions, what might be a mild disease or mild infection in a young person or a person who is in good health, will have a greater impact on you.”
She said this was why the Australian Technical Advisory Group for Immunisation (Atagi) had recommended boosters for those people who are severely immunocompromised. On Wednesday the government said it intended booster shots to be rolled out to the aged care sector within weeks, and to be available to the whole population by the end of the year.
“We don’t have the final data on this yet available, but there will also be a proportion of patients who have Covid, but they are already dying for another reason,” Nguyen said. “They may be fully vaccinated, they have a mild form of Covid, but maybe it’s brought out more severe heart failure, which they had previously.”
Between 16 June and 18 October there were 61 deaths among fully vaccinated people in New South Wales, from a total of 479 Covid deaths. Data provided to Guardian Australia by NSW Health shows of the deaths in the fully vaccinated, all were aged 50 or above. Of those who died, five were in their 50s, one in their 60s, 17 in their 70s, 22 in their 80s and 16 in their 90s.
On Friday, the ABC revealed 36 of the 49 aged care residents who have died after contracting Covid during NSW’s Delta outbreak were fully vaccinated. All had underlying health conditions or were in palliative care.
Prof Allen Cheng, the director of the infection prevention and healthcare epidemiology unit at Alfred Health, said only a small number of deaths had occurred in fully vaccinated people.
“I understand they have been mostly in older people over 70 years of age, with some in aged care facilities,” he said.
The impact of the vaccine in reducing deaths among elderly people had been significant, Cheng said. Last year, before a vaccine was available, the mortality of people in their 80s with Covid was about 30%, he said.
Cheng said it was likely that given Australia’s extraordinary vaccination coverage the bulk of people who became severely unwell or died with Covid-19 from now were fully vaccinated.
“At some point, there will be more people with infections that are vaccinated than those that are not vaccinated,” he said. “As a simple thought experiment – if everyone is vaccinated, then the only cases we would have would be in vaccinated people.”
Nguyen agreed that with high vaccination rates, “in the future a greater proportion of those in intensive care will be those who are fully vaccinated and who are frail with other conditions, rather than people who are unvaccinated”.
“But keep in mind that even at 95% of eligible people vaccinated, that still leaves a lot of people unvaccinated. Which is why we anticipate that in living with Covid, there will be a baseline number of Covid patients in intensive care across NSW into the foreseeable future, and we’re certainly planning for that.
“What that actual baseline number is, we’re still not quite sure.”
Cheng said measures could be taken to further protect those at risk of severe disease despite vaccination. Atagi, which Cheng co-chairs, is still assessing the data for booster shots and it may make further recommendationsabout their use.
Once the recommendation of booster shots was confirmed, the additional protection of the general population would further reduce the risk of the most vulnerable becoming infected.
Australia is also using the novel monoclonal antibody treatment sotrovimab, which has been shown to dramatically reduce hospitalisation and risk of death in adults who are at risk of developing severe Covid-19.
“New monoclonal antibodies may provide additional protection, particularly in immunosuppressed people,” Cheng said. “Newer antiviral treatments may also become useful, although they are still under evaluation.”