1.

Vaccine doses, daily new confirmed cases, ICU patients, and death cases in Belgium.

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Stringency index in Belgium.

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Recueil d'histoire littéraire.

1.

S1 Annex -

1.

PRISMA 2009 checklist.

1.

PRISMA flow diagram of the included studies.

1.

Rate of uncontrolled asthma assessed using the GINA symptom control.

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Regression plot of rate of uncontrolled asthma against smoking.

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Rate of well-controlled asthma assessed using the GINA symptom control.

1.

Rate of partly controlled asthma assessed using the GINA symptom control.