" The vaccine " is not a drug, and malaria is not caused by a virus.

Ivermectin is unlicensed in the UK, may be used for treatment of strongyloides and onchocerciasis infections, also some cases of scabies. It has a long list of potential side effects, some severe, which may not immediately become apparent.

Anyone with " blood pressure going through the roof " needs urgent medical treatment ( and a young person with this may well have a treatable cause ).

I've explained ( again ) our immune system in the "Health Issues" section. If that seems daunting, try reading the 500+ page "Roitt's Essential Immunology" textbook !