Final answer:
The government can help equalize the quantity supplied and the quantity demanded by implementing subsidy programs and imposing price ceilings.
Step-by-step explanation:
One way the government can help equalize the quantity supplied and the quantity demanded is by implementing subsidy programs. For example, the government can provide vouchers to citizens who wish to get vaccinated. These vouchers act as income and can only be used to purchase flu shots. By ensuring that the value of the voucher is equal to the per-unit spillover benefits, the government can increase the market equilibrium to a socially desirable level.
Another way the government can help is by imposing price ceilings. Price ceilings set a maximum price that sellers can legally charge for a good or service. This can prevent prices from skyrocketing to levels that only a few individuals can afford and create fairness in the market.