What is the difference between the Haemophilus influenzae vaccination, the influenza vaccination and flu?

when and why are the vaccinations given?
I know that haemophilus influenzae is a bacteria and
influenza is a virus

well for one thing - the H. influenzae vaccine is usually given when one is young, and should be good for life (or a very long time)

the flu vaccine (the one for the virus) is something that they have to make and give EVERY year - it is based on the strain of virus that they THINK will cause the flu in the coming year.

Flu is a common virus, which we all can get and overcome after a few days of rest.
Haemophilus influenzae, is a serious disease, which can lead to opurtinistic infections and is deadly if not treated soon. H. influenzae is responsible for a wide range of clinical diseases, meningitis being one of the most serious ones. Since infants and small children are at greater risk, they are vaccinated to prevent meningitis.
All children should have a vaccine approved for infants beginning at 2 months. Depending on the type used, the recommended schedule for infants will vary. All unvaccinated children 15 - 59 months old should receive a single dose of conjugate vaccine. Children 60 months of age or older and adults normally do not need to be immunized.

Flu vaccination is administered to people who have weak immune systems, like
People 65 years and older;
People who live in nursing homes and other long-term care facilities that house those with long-term illnesses;
Adults and children 6 months and older with chronic heart or lung conditions, including asthma;
Adults and children 6 months and older who needed regular medical care or were in a hospital during the previous year because of a metabolic disease (like diabetes), chronic kidney disease, or weakened immune system (including immune system problems caused by medicines or by infection with human immunodeficiency virus [HIV/AIDS ]);
Children 6 months to 18 years of age who are on long-term aspirin therapy. (Children given aspirin while they have influenza are at risk of Reye syndrome.);
Women who will be pregnant during the influenza season;
All children 6 to 23 months of age;
People with any condition that can compromise respiratory function or the handling of respiratory secretions (that is, a condition that makes it hard to breathe or swallow, such as brain injury or disease, spinal cord injuries, seizure disorders, or other nerve or muscle disorders.)

but it is given as a precautory measure only.

Bacillus inoculations can/do attack the t
outer coating of the bacteria, blocking specific cell wall reproduction, influenza is intra-cellular using host DNA/cells to reproduce, thus the inoculation has to highly specifis to that variation

The hib vaccination is given to babies to prevent them from getting meningitis.

The flu vaccination is given to anyone that wants it to ward off certain strains of the flu virus.