In the case of COVID-19, the mRNA vaccine can create stronger immunity than the natural immunity gained by contracting the disease.

People who have already been affected by COVID-19 can also benefit from the mRNA vaccine.

source:

(en)
People who already had COVID-19 should still get vaccinated, scientists urge
https://www.nationalgeographic.com/science/article/people-who-already-had-covid-19-should-still-get-vaccinated-scientists-urge

(ja)
新型コロナ感染者もワクチンを接種した方がいい理由
感染済みでも免疫を強化できるうえ、変異にも強い
https://natgeo.nikkeibp.co.jp/atcl/news/21/080600392/