Giving vitamins to a 2-year-old asthma child to prevent asthma attacks during a cold is not proven to be effective. It is recommended to focus on non-pharmacological measures such as ensuring the child consumes plenty of fruits and vegetables, gets enough sleep, manages stress well, and practices good hygiene habits. It is also important to be aware of triggers for asthma attacks and take preventive steps. Regular use of maintenance inhalers and saline solutions for sinus hygiene can also help prevent cold-related asthma symptoms.