SARS‐CoV‐2 infection is associated with higher incidences of hospitalisation for several respiratory and non‐respiratory conditions.

A Victorian study comprised 20,594 laboratory-confirmed COVID‐19 cases notified between January 2020 and May 2021, ahead of the Delta and Omicron variants and widespread COVID-19 vaccination.

Using linked datasets, the study compared the condition‐specific incidence of hospitalisation for the 12 months before and 12 months after SARS‐CoV‐2 infection.

The study, published in The MJA [link here], found 9,336 hospital admissions of any cause within twelve months of COVID‐19 onset were recorded for 4,339 people (21.1% of the cohort).

“The incidence of hospitalisation with myocarditis and pericarditis (IRR, 14.8; 95% CI, 3.2–68.3), thrombocytopenia (IRR, 7.4; 95% CI, 4.4–12.5), coagulative disorders (IRR, 4.6; 95% CI, 1.5–14.5), acute kidney failure (IRR, 4.5; 95% CI, 3.8–5.3), acute myocardial infarction (IRR, 3.9; 95% CI, 2.6–5.8), and cerebral infarction (IRR, 2.3; 95% CI, 1.4–3.9) were each higher during the post‐exposure period than during the baseline period, as were those of venous thromboembolic events (pulmonary embolism: IRR, 6.4; 95% CI, 3.6–11.4; lower limb embolism, phlebitis and thrombophlebitis: IRR, 5.7; 95% CI, 2.8–11.7),” it said.

The rate of hospitalisation with respiratory conditions was markedly higher post‐exposure than the baseline period, including infectious respiratory events (IRR, 15.2; 95% CI, 13.2–17.4), non‐infectious respiratory events (IRR, 9.1; 95% CI, 7.6–10.9), and asthma events (IRR, 6.1; 95% CI, 4.8–7.8).

As well, the rate of hospitalisation with control conditions including injuries and urinary tract infections were also higher during the post‐exposure period than the baseline period.

The study found the risk of hospitalisation for cardiovascular conditions was highest around the time of the COVID-19 infection, while venous thromboembolic events were highest 14-29 days after COVID-19 onset, and respiratory symptom‐related hospitalisations were highest up to 30 days after COVID‐19 onset.

Regarding the risk of PE especially, it said a low threshold for investigation was warranted in people with COVID‐19 or a past history of SARS‐CoV‐2 infection.

The investigators, including infectious diseases physician Professor Allen Cheng and Chief Health Officer Professor Brett Sutton, said the increases in hospitalisation rates were statistically and clinically significant, despite the often small numbers.

“Further, we found that the incidence of hospitalisation with severe cardiac and thromboembolic events after SARS‐CoV‐2 infection was higher than the reported risk of these events after vaccination.”

The investigators said their findings regarding non-respiratory conditions after SARS-CoV-19 infections were consistent with other evidence.

“These findings — coupled with growing knowledge of the post‐COVID‐19 condition (“long COVID”), defined as the presence of symptoms lasting at least two months in a person with a history of SARS‐CoV‐2 infection and not explained by an alternative diagnosis, usually three months after COVID‐19 onset — highlight the continuing clinical, public health, and societal challenges for managing COVID‐19.”

“Our findings indicate the need for ongoing COVID‐19 mitigation measures, including vaccination, and support the early diagnosis and management of complications in people with histories of SARS‐CoV‐2 infection.”

They said future research should ascertain the impact of COVID-19 vaccination on the increased risk of specific complications.