High numbers of vaccinated hospitalized in Australia not evidence of higher risk
High numbers of vaccinated hospitalized in Australia not evidence of higher risk
(Reuters) - Data from Australia on Covid-19 hospitalizations based on vaccination status has circulated online without context, alongside false claims that vaccinated people are at higher risk of hospitalization with the virus than the unvaccinated.
A link to a newsletter article titled “BOMBSHELL – Pandemic of the vaccinated” is circulating on social media featuring data from New South Wales (NSW) about those hospitalized with Covid in the two weeks ending Dec. 31, 2022 (here, here and here).
The newsletter author shared some of the findings on Twitter, including that 100% of those hospitalized were vaccinated, while 0% were unvaccinated. The posts also suggested that the more vaccine doses people received, the higher the chance of Covid-19 hospitalization (here, here and here).
The newsletter stated that this shows having had zero vaccines means a 0% chance of being hospitalized with Covid-19, a claim that was later removed from the newsletter article (here).
However, the posts miss key context that some 96% of all adults, and nearly 100% of those over age 65 in NSW, have been vaccinated against Covid-19. The data also show that hospitalizations and deaths predominantly occurred in the elderly, who are both more likely to be vaccinated and at higher risk of serious outcomes from the virus.
“The assertions made in these social media posts are completely incorrect,” a NSW Health spokesperson told Reuters in a statement via email.
AUSTRALIAN DATA
NSW surveillance data for the two weeks ending Dec. 31, 2022, does show that no individuals confirmed to have been unvaccinated were admitted to hospital with a Covid diagnosis during the period (399 people had an unknown vaccination status). And, among the total 1,919 people who were admitted to the hospital or ICU with Covid, the largest proportion (868 people) had received four vaccine doses (here, page 4).
Of the 1,919 people admitted with Covid, 1,451 (76%) were age 60 or older.
There is no evidence that vaccination increased a person’s chances of hospitalization from Covid-19, the NSW Health spokesperson said.
According to NSW Health, 95.8% of the NSW population over the age of 16 and nearly 100% of over-65s have received at least two vaccine doses.
In Australia as a whole, 97.4% of adults have received at least one Covid-19 vaccine, while 96% have received two doses (here).
NUMBERS VS PROPORTION
The Department of Health and Aged Care (DHAC) told Reuters that in a highly-vaccinated population such as Australia’s, the total number of COVID-19 infections, including hospitalization, ICU admission or death, is expected to be predominantly among vaccinated people.
“This does not mean the vaccines are not working,” a spokesperson said.
Reuters has previously fact-checked false claims that a higher proportion of vaccinated people contracting COVID or dying from it reflects vaccine effectiveness (here ) (here ).
Reuters previously documented that high Covid-19 vaccination rates in NSW mean that those admitted to hospital are likely to have been vaccinated (here).
While the total number of severe cases among the vaccinated will be higher, given it’s a much larger group of people, the DHAC spokesperson explained, the proportion of severe cases in the unvaccinated population will be far greater (because it is a smaller population, and vaccination is associated with improved protection against severe illness) than the vaccinated group.
Independent research supports this pattern. For example, a global model of Covid-19 transmission and vaccination found that an individual’s risk of hospitalization and death from Covid is higher if they are unvaccinated than if they are vaccinated (here ).
CONFOUNDERS
Those who are most at risk of severe disease, including the elderly and immunocompromised, according to the DHAC, are also more likely to be vaccinated, which confounds analysis of severe cases and deaths by vaccination status.
The data from NSW show that the large majority of those admitted to hospital with Covid-19 in the two weeks up to Dec. 31, 2022 were over age 65 (here).
The NSW data do not include information about the patients’ health status or details of other illnesses. Among 95 people who died with Covid-19 during the study period – in or outside of the hospital - 35 were aged care residents and six were confirmed to have been unvaccinated, while the vaccination status of another seven was unknown, the report shows.
The NSW surveillance report does not include an analysis of risk for hospitalization based on vaccination status. The report notes on page 1 that, going forward, the report will use “formal data-linkage and analyses which account for age, previous infection, underlying illness and other factors that impact on” measurements of vaccine effectiveness in local populations.
The relationship between vaccination and risk of serious outcomes from Covid-19 infection, the NSW Health spokesperson said, “can no longer be determined using these surveillance data alone.”
Reuters contacted newsletter author Peter Imanuelsen but did not receive a response.
VERDICT
Missing context. Comparisons of New South Wales hospitalization figures based on vaccination status omit the fact that nearly all of the region’s adults are vaccinated against Covid-19. Suggestions that vaccination increases risk of Covid-19 illness are not supported by the data or analyses presented.
