Vitacid Calcium effervescent tablets to strengthen immunity and bones. Vitacid Calcium effervescent tablets are characterized by being a compound of vitamin C, and calcium works as a nutritional supplement to compensate for calcium deficiency, or low levels of vitamin C in the body. Vitacid Calcium effervescent tablets work to enhance immunity due to their vitamin C content, and this formula is useful for patients with allergies to vitamin C as calcium makes it lighter on the stomach.