Thread by @ZdenekVrozina

A new Dutch study in BMJ Open 2025 followed people 2 years after COVID-19.
Even among those never hospitalized, 43% still had persistent symptoms.
This is a massive population-level impact.🧵

Hospitalized patients had higher prevalence of post-COVID (65%).
But they are a fraction of all infections.
The real burden comes from the huge group of mild cases!

The CORFU study = Corona Follow Up.
4,200 participants, 7 patient cohorts + controls.
Follow up at 3, 6, 12, 18, and 24 months.

Groups.
non-hospitalized
hospitalized (ward)
ICU
controls (no COVID)
At 24 months - 901 patients, 434 controls.

Symptoms tracked - fatigue, sleep problems, brain fog, muscle weakness, shortness of breath, palpitations, loss of smell/taste, etc.
Quality of life measured by
EQ-5D-5L - 5 health domains
EQ-VAS - self-rated health (0–100)
HUS - health utility score (0–1)

Most common symptoms (non-hospitalized vs controls):
Fatigue 29% vs 19%
Sleep problems 18% vs 12%
Cognitive issues 14% vs 4% (sic!)
Shortness of breath 12% vs 4%
Muscle weakness/pain 16% vs 11%
Overall - 43% of non-hospitalized had ≥1 symptom after 2 years.

Quality of life at 2 years.
Controls - EQ-VAS 75.6 / HUS 0.84
Patients - EQ-VAS 70–72 / HUS 0.77–0.81

That drop is equivalent to living with a chronic illness! And importantly - seen across all groups, not just ICU.

So Long COVID ≠ only PICS (post-intensive care syndrome).

The impact is everywhere.
Work & school - fatigue, brain fog, poor sleep
Healthcare - repeated visits, rehab, mental health, crowded clinics
Society - lower quality of life, disability, early exits from workforce

Policy signal.
Even if only 40% of non-hospitalized are affected, they represent the largest absolute burden.

Long COVID is not rare. It is a population-wide phenomenon reshaping health, education, and the economy.

And this is the reality in many countries:
Hundreds of thousands living with fatigue, cognitive problems, sleep disruption, or breathlessness - often without adequate support.

The result? A damaged population.
The consequence? Enormous economic costs.
These national economic losses expose a fundamental failure of public health. And of governments. @szupraha @ZdravkoOnline

Klein at al., Two years and counting: a prospective cohort study on the scope and severity of post-COVID symptoms across diverse patient groups in the Netherlands - insights from the CORFU study. bmjopen.bmj.com/content/15/9/e…

Most infections in this study happened before vaccines and during the wild type/Alpha/Delta waves.
By 24 months, 89% had been vaccinated.
Later follow-ups did include some Omicron cases, but they were a minority.