, an excellent resource that discusses your questions is Aaron Boster MD, who has made numerous videos about MS and its treatments on youtube. Go to the search box there and type: Aaron Boster Ocrevus. You'll see a bunch of videos pop up that address the most effective DMDs, Ocrevus, Tysabri, Tecfidera, Lemtrada, Gilenya, and a host of related discussions. I've learned more about MS and its treatments from Dr. Boster than from the whole MS online (and off-line) community combined.
On a personal note, I've been on Tecfidera for the past six years. After a year on Tysabri and six on Tecfidera--both of which carry the risk of PML--I have no worries about getting the infection. You have to be JCV positive to be at risk, and even then the risk is quite low. A recent test for the JC Virus was negative. Some people switch to a drug that has no PML risk when they test positive, but many stay on those at-risk drugs if they are effective at stabilizing the patient's disease course. It's a personal choice.
The only side effects I've experienced from Tecfidera are flushing and tingling. But, bear in mind that everyone experiences these drugs differently. Some suffer digestive problems and worse.
Dr. Boster favors aggressively treating the new patient and discusses why in one of his videos. I hope you'll spend time watching those, you'll learn so much. In the end, you'll have the last word about whatever treatment plan is chosen. Remember that nothing is written in stone. You can change your mind and your treatment at any time.