While the study proved a big COVID-19 myth wrong, Vitamin C and Zinc are both potent nutrients which are vital for sustaining body functioning.
Vitamin C and Zinc also contain infection-fighting properties, which is one of the reasons why Vitamin C is actively prescribed to people with a cold, cough or chronic infections. The same extends for benefits of zinc, which a lot of people are surprisingly deficient in.
However, thinking of these nutrients as the perfect immunity boosters may not hold so true.