No need to excuse ignorance, some of us have more experience than others, that’s all.
PML is a rather nasty viral beast that could (this is incredibly unlikely) invade a persons system if they have the side effect from Tecfidera that your lymphocytes dip very badly and remain that way. Lymphocytes are the type of white blood cells that fight against viruses - like PML. To prevent the danger of this and other viruses attacking you, your blood is tested very regularly. If the level of lymphocytes dips dangerously low and stays that way, you’ll be taken off Tecfidera and your lymphocytes count will recover. So it would be wrong to not mention PML, but at the same time, it’s not at all likely.
The most likely side effects you’d suffer with Tecfidera are an upset stomach in the early days. The main way of preventing this is to sandwich the pills in between two amounts of food. So for example, people are advised to have something like porridge for breakfast, take a pill, then eat some toast with peanut butter. The other way of decreasing the early stomach issues is to arrange with your nurse and delivery company to slow down the introduction of the Tecfidera. Ordinarily, people are given one week of half dose pills for the two daily doses, then from week two, increase to the full dose. It is possible to arrange one pill at half dose for the first week, two doses of the half dose in week two, one half and one full dose for week three and up to the full strength for both doses in week four.
The other common side effect is flushing, a sudden rush of blood to the face (typically), but many people don’t get this, or have it once and never again.
I took Tecfidera for about 8 months, I had to stop after my lymphocytes dipped and stayed low. They recovered, it’s fairly common, so it’s a disappointment, but not a dangerous risk. It’s still a good drug and works brilliantly for the majority of people who take it. They get past any initial unsettled stomach issues and just take their meds and don’t worry about any side effects.
Good luck with your choice.