Are we at risk ?

My eldest sister D ( who we don't see ) had whopping cough .. My other sister M, went and saw her yesterday , she had had her whopping cough needle 3 years ago when DD1 was born ..
My eldest sister has been on antibiotics for 5 days ..

DD2 is 11 weeks old now and has only had one shot ..

Should we avoid seeing sister M now ? She lives with my mum as well ..
Should we avoid sister M and my mum ?

I'm honestly not sure, but if it would make you feel more at ease, look up the period of time between exposure and when symptoms occur and maybe try to avoid contact for that amount of time?

I've just looked into this because my brother has whooping cough, and was diagnosed just before I had DS2. My SIL came into the hospital to visit me, but my brother stayed at home.

My SIL has been immunised because she is a nurse so she's fully up to date. My brother is on antibiotics - which apparently, stops the spread if you interact with them after the first 5 days of the dose.

I'm immunised for WC (when DD3 was 8 months old) - and the booster lasts for a fair while from what we could find out via google.

Its a scary thing - my mum is going to get her booster shot for WC because she hasn't had one in like, forever lol Just make sure if anyone coughs, they don't cough in the direction of the baby!

Thanks guys , it's just really so scary , it's such a terrible thing to get . DD2 already had a cough and cold when she was 4 weeks old , which was bad enough and such a worry that it would turn into WC ...
I don't know if I want to risk her being around people who have been around someone with a confirmed case of it :/