The risk of death, hospitalisation and serious health issues from COVID-19 jumps significantly with reinfection compared with a first bout of the virus, regardless of your vaccination status, a study has found, with three times more chance of lung problems and heart conditions, and 60% more chance of neurological disorders than those who have been infected only once.
“Reinfection with COVID-19 increases the risk of both acute outcomes and long COVID,” said Dr Ziyad Al-Aly of Washington University School of Medicine in St Louis. “This was evident in unvaccinated, vaccinated and boosted people.”
The findings were drawn from US Department of Veterans Affairs (VA) data collected from 1 March 2020 until 6 April 2022 on 443 588 patients with one SARS-CoV-2 infection, 40 947 with two or more infections, and 5.3m non-infected individuals. Most of the study subjects were male.
Reuters reports that reinfected patients had a more than doubled risk of death and a more than tripled risk of hospitalisation compared with those who were infected with COVID-19 just once. They also had elevated risks for problems with lungs, heart, blood, kidneys, diabetes, mental health, bones and muscles, and neurological disorders, according to the study, which was published in Nature Medicine.
“Even if one had prior infection and was vaccinated – meaning they had double immunity from previous infection plus vaccines – they are still susceptible to adverse outcomes upon reinfection,” Al-Aly, the study leader, said.
The higher risks were most pronounced in the first month after reinfection but were still evident six months later, researchers found.
Experts not involved with the study said the VA population does not reflect the general population.
Patients at VA health facilities are generally older, sicker people and often men, a group that would typically have more than normal health complications, said John Moore, a professor of microbiology and immunology at Weill Cornell Medical College in New York.
The researchers said cumulative risks and burdens of repeat infection increased with the number of infections, even after accounting for differences in COVID variants such as Delta, Omicron and BA.5.
However, Dr Celine Gounder, an infectious disease epidemiologist and an editor-at-large at Kaiser Health News, said there seemed to be a “plateauing effect with multiple infections”, with less of a jump in risk after the second infection.
“The good news there is that the better people are protected with immunity, the less likely the risk of developing some of the complications over time,” she added.
Still, Al-Aly cautioned that people should not let their guard down. “We had started seeing a lot of patients coming to the clinic with an air of invincibility,” he told Reuters. “They wondered: ‘Does getting a reinfection really matter?’ The answer is yes, it absolutely does.”
Study details
Acute and postacute sequelae associated with SARS-CoV-2 reinfection
Benjamin Bowe, Yan Xie & Ziyad Al-Aly.
Published in Nature Medicine on 11 November 2022
Abstract
First infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with increased risk of acute and postacute death and sequelae in various organ systems. Whether reinfection adds to risks incurred after first infection is unclear. Here we used the US Department of Veterans Affairs’ national healthcare database to build a cohort of individuals with one SARS-CoV-2 infection (n = 443,588), reinfection (two or more infections, n = 40,947) and a noninfected control (n = 5,334,729). We used inverse probability-weighted survival models to estimate risks and 6-month burdens of death, hospitalisation and incident sequelae. Compared to no reinfection, reinfection contributed additional risks of death (hazard ratio (HR) = 2.17, 95% confidence intervals (CI) 1.93–2.45), hospitalisation (HR = 3.32, 95% CI 3.13–3.51) and sequelae including pulmonary, cardiovascular, haematological, diabetes, gastrointestinal, kidney, mental health, musculoskeletal and neurological disorders. The risks were evident regardless of vaccination status. The risks were most pronounced in the acute phase but persisted in the postacute phase at 6 months.
Compared to noninfected controls, cumulative risks and burdens of repeat infection increased according to the number of infections. Limitations included a cohort of mostly white males. The evidence shows that reinfection further increases risks of death, hospitalisation and sequelae in multiple organ systems in the acute and postacute phase. Reducing overall burden of death and disease due to SARS-CoV-2 will require strategies for reinfection prevention.
Nature article – Acute and postacute sequelae associated with SARS-CoV-2 reinfection (Open access)
Reuters article – Repeat COVID is riskier than first infection, study finds (Restricted access)
See more from MedicalBrief archives:
COVID-19 reinfection twice as likely in the unvaccinated — CDC study
‘Sobering’ findings on natural protection against COVID-19 reinfection
NICD analysis finds Omicron subvariant increases risk of reinfection