Vaccination after COVID-19 hospital stay may protect against long COVIDA study yesterday in Clinical Microbiology and Infection suggests that natural infection, but not immunity acquired from COVID-19 vaccinations, is linked to the development of long COVID-19, or symptoms that persist up to a year after acute infection.The prospective study was based on 479 COVID-19 patients originally seen at the Udine Hospital in Italy from March to May 2020.
Researchers conducted interviews 6 and 12 months after acute infection, and vaccination status was obtained, as vaccines had become available in the interim.
The investigators also obtained two different serologic assays to distinguish between response to vaccination (receptor-binding domain [RBD] SARS-CoV-2 immunoglobulin G [IgG]) and to natural infection (non-RBD- SARS-CoV-2 IgG).Of the participants, 47.2% experienced COVID-19 symptoms 1 year after infection, including 85 (30.6%) who reported the onset of new post-COVID-19 symptoms at 12 months.
There were no significant differences in the worsening of post-COVID 19 symptoms (22.7% vs 15.8%, P = 0.209) among vaccinated (132) and unvaccinated (347) patients.The authors said the presence of non-RBD SARS-CoV-2 IgG induced by natural infection showed a significant association with post-COVID-19 syndrome (odds ratio [OR]; 1.35, 95% confidence interval [CI], 1.11 to 1.64; P = 0.003), while the presence of RBD SARS-CoV-2 IgG was not associated with the occurrence of post-COVID-19 syndrome (>2,500 units per milliliter [U/mL] vs 0.9–2,500 U/mL, OR 1.36; 95% CI 0.62 to 3.00; P = 0.441)."The persistence of a high titre serological response induced by natural infection but not by vaccination may play a role in long COVID-19," the authors