Hi XXXXXX
To give you a back ground… vaccines are often injectable and at times oral ingestable parts or whole of the inactivated live or killed components or whole of viruses or bacteria prepared artificially or by using dna or rna or whole microbe with or without culture on specific human or nonhuman tissues…
Vaccines are almost alway studied for proven safety and efficacy by regulating authority before licensing for marketting.
Some vaccines give life time protection and some for few years and some may need repeated courses of the same.
So when you take a vaccine and complete its course… its definitely for some benefit at no loss… except its cost… some vaccines have been blamed for its side effects but science disproved most.

Coming to your query… by now you must have understood that all vaccines are safe and are recommended to take the protection considering the risks associated with respective disease even if it is one in million…
Rotavirus and flu virus vaccines are highly marketed due to being newly discovered… flu epidemic has really created a scare in community… rotavirus vaccine is often given as 2 doses one month apart with last dose given before 30 week age. Another company has 3 dose rotavirus scheme…
Flu vaccine is prepared freshly every year depending on the strains prevalent in that year… its best taken around april may to get protection from the flu that may come next 8 months… flu vaccine cannot prevent cough cold etc . It has to be taken every year with 2 doses for first year of starting… 1 month apart and earliest by 20 months… new flu vaccines are much safer than blamed old ones… . Rotavirus vaccine can't give protection from every loose motions and effect is primary to reduce severity of infant diarrhea.…

Per se no vaccine is required for growth and survival… but protection is desirable …

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