Brief Answer:
follow the advises...maintain a healthy lifestyle...

Detailed Answer:

Hello,

I've gone through your query and understand your concerns.

Well, first of all, please note that in an otherwise healthy adult, there's no need for any additional immunization/vaccinations (they are primarily recommended for the extreme age groups i.e. children and elderly population)...

The main protection from any pathogen is provided by our body's own immunity, and that's mostly enough...Vaccinations and flu-shots aren't the right choices in this scenario...

Since both of you're falling sick repeatedly, it's important to get a 'Comprehensive health check-up' done under supervision of an Internal Medicine Specialist in the first place to look for the possible causes in the first place (causes can be from anemia to vitamins/minerals/nutritional/hormonal deficiencies and several others)...

Yes, surrounding environment can definitely play a big role along with this. For this, you can install good-quality air-purifier at home (now-a-days all state of the art companies send their representatives at home for air-quality check in the first place and based on the results recommend the necessary models). While going out in over-crowded places use face-mask, stay away from direct exposure to AC ducts and vents as well as construction areas.

Along with this, it's extremely important to eat timely and healthy diet. Never to skip breakfast, don't go out for a prolonged duration on empty stomach, avoid smoking/alcohol (if at all do) at any cost (they're another big contributory factor which hampers the body's immunity like anything).

Finally, some environmental agents (dust, pollen, mites etc.) can also act as an allergen from time to time, thus worsen the cough-cold and flu-like situations. To identify the offending agents and for further management, both of you should also get Comprehensive Allergic pannel testing done.

I've tried to make it as simple as possible for you to understand, let me know if there are any further doubts/queries.

Take Care
Kind Regards

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