usa 四价流感疫苗 price higher and higher but it didn't work for me in 2019

Protection from influenza vaccine is thought to persist for at least 6 months.

It has been recognized for many years that people 65 years and older are at high risk of ... The high dose vaccine (brand name Fluzone High-Dose) contains four times the amount

--i got flu shot  10/19/19 in cosco with low price  $20.37, but infected H1N1 in taiwan Jan. 15,2020 which i didnt visit any doctor until the end of Aug,2020 i was fully recovered(no abnormal caughing since Sep)

my spouse got flu shot in our township senior center sep, 2019. he didnt infected by me except a couple weeks quite unconfortable(4days fever then dried caughing). that made me thought he got better quality flu shot.

so i decided to get flu shot in senior center this year and found out the price went high to $25(not senior dose, last year $20 but not sure is 3价：甲型H1N1+ H3N2+ B型Victoria系（BV） or 四价流感疫苗 added B型 Yamagata).

And then found it is called 四价流感疫苗 and my spouse told me last year he got "Senior dose" because his age(70+) qualified to get "Senior dose(must 65+)" but not me.

i would say because it is for multiple virus(四价) so many americans just felt like me that the flu shot is useless.

while the 四价流感疫苗  is $40 without insurance, "Senior dose"without insurance cost $69.99, with  GoodRx coupon is $55.

Should i just stay home and shopping with wearing hat with face mask plus 口罩? in here i can see in grocery stores every one wearing 口罩 that can reduce flu infection without doubt.