i think the vaccination is to prevent a certain infection that can cause many complications for those with sickle cell:
"Increased risk of severe bacterial infections is due to loss of functioning spleen tissue (and comparable to the risk of infections after having the spleen removed surgically). These infections are typically caused by encapsulated organisms such as Streptococcus pneumoniae and Haemophilus influenzae. Daily penicillin prophylaxis is the most commonly used treatment during childhood, with some haematologists continuing treatment indefinitely. Patients benefit today from routine vaccination for S. pneumoniae."
https://en.wikipedia.org/wiki/Sickle_cell_disease#Complications

also it says this:
"Sickle cell disease occurs more commonly among people whose ancestors lived in tropical and subtropical sub-Saharan regions where malaria is or was common. Where malaria is common, carrying a single sickle cell allele (trait) confers a heterozygote advantage; humans with one of the two alleles of sickle cell disease show less severe symptoms when infected with malaria"
https://en.wikipedia.org/wiki/Sickle_cell_disease#Epidemiology

so i guess the reason why its more common in your area is because people with sickle cell have some advantage at surviving malaria, hence individuals with sickle cell are more likely to pass on their genes. maybe it does trigger the pain from your sickle cell but perhaps also prevents your malaria to develop to cerebral malaria (the most deadliest complication of malaria).

actually the CDC has a more elaborate list of recommended vaccinations:
https://www.cdc.gov/ncbddd/sicklecell/healthyliving-prevent-infection.html

also its saying u should wash hands frequently even if there is no corona,
and if u have siblings with sickle cell its best if they take antibiotics daily until age of 5.