Re: a way to Ving or RV?
If you wanted to use "V + ing", you can do it by changing "to" to "of" - but not in all contexts.
Originally Posted by terrenziqq
Also, I find "a major way" rather unnatural. I would use "an important way" or "the most important way". It's also difficult to "prevent influenza" but it's possible to "prevent/stem/slow/control the spread of influenza".
Washing [your/one's] hands regularly is a good way to prevent [the spread of] influenza.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.