A study published in Nature recently (30/11/23) aimed to determine the true prevalence of long Covid symptoms in Scotland that are attributable to prior SARS-CoV-2 infection. It included almost 200,000 adults – half with confirmed symptomatic infections and half matched controls never infected.
At 6 months follow-up, 64.5% of previously infected people reported at least 1 ongoing symptom compared to 50.8% of those never infected. The crude prevalence of symptoms attributable to infection was 13.8%. After adjustment for confounders, the attributable prevalence was 6.6%.
Similar attributable prevalence estimates were obtained at 12 months (6.5%) and 18 months (10.4%), indicating symptoms may persist up to 18 months post-infection for around 1 in 10 people.
Prevalence was higher in women, those more vaccinated pre-infection, and people infected later in the pandemic. It was lower in those with more pre-existing conditions. Following severe infection, prevalence reached 79-84% depending on follow-up time.
Many common symptoms reported post-infection are non-specific. The findings suggest the likelihood of mistakenly attributing symptoms to long Covid when they may be unrelated. Careful diagnosis is warranted.
In conclusion, around 6-10% of infected people have ongoing symptoms for up to 18 months attributable to SARS-CoV-2 infection. This is lower than some previous estimates. Support for long Covid sufferers and more research on causes and treatments should be priorities.
You can read the full report here.
