I've not contracted any contagious illness in at least 3 yrs+; whereas I used to catch some resp virus 3-4 times yearly due to being in the medical field and having asthma, which sometimes lead to a secondary infection. Pneumonia once. I use other supps but I credit Vit D3 for my strong immunity, plus I sanitize my hands multiple times daily. This is also paramount. But check with your primary care doc first as they say.
best preventative - Vit D3; do you have any info on 3k dosage; do you get blood work to test for levels?
We’re doing the same thing along with taking vitamin C.
Last year was a horrible year for my daughter with asthma. She was constantly getting sick, it would trigger her asthma, and it would take 2 weeks to get over it.
My other daughter was diagnosed with low vitamin d because she is on anti-seizure medication and that is one of the side effects.
I started reading about low vitamin d and how if affects the immune system. Now, all of us are taking it (at varying levels).
We’ll see if it helps.