Vitamin D deficiencies can reduce vaccine efficacy and also increase the severity of COVID infection in individuals, confirms medical experts. Studies have found that young adults are about 4 times more likely to have Vitamin D deficiencies as compared to older adults due to cultural and social changes that have taken over in the past few decades. Vitamin D deficiency is directly associated with the exposure of the skin to the sun. “We see even the traffic police are found Vitamin D deficient despite having good exposure to sunlight. They spend reasonably good time in the sunlight but their skin and face are covered and not exposed to the sunlight,” says Dr Amitav Banerjee, Professor and Head of Community Medicines, D Y Patil Medical College, Pune.