Flu shots may well be required for all daycare and preschool children in New York after today's decision by city health officials.

The Board of Health is scheduled to vote later today on a measure backed by Mayor Michael Bloomberg's administration that would mandate annual flu vaccinations by Dec. 31 each year for all children under 5 in city-licensed preschools and daycare centers.

The end-of-the-year deadline coincides with a period before the yearly flu season typically peaks.

According to data from the Centers for Disease Control and Prevention, the flu season generally starts as early as October, the number of cases rising substantially by December and reaching its highest levels sometime in January through March.

City statistics suggest the shots initiative could prevent more than 20,000 young children annually from suffering the flu.

If the measure is enacted, a daycare or preschool can exclude a child from its facility if he or she doesn't get the vaccine. On the flip side, if a facility fails to keep up-to-date vaccination records, it could face a fine.

Mandating a flu vaccine for young children is uncommon, as only New Jersey and Connecticut have similar laws for some schools. There are, however, NYC requirements that children in the same age bracket as those included in the flu shot initiative receive the MMR (measles, mumps, rubella), polio, whooping cough, chickenpox and tetanus vaccines.

It's estimated the flu shot mandate would cover about 150,000 NYC residents who are 5 years or less.

A flu season can vary in its severity, but children and the elderly are often the most affected.

Federal health records show over the previous 10 flu seasons before 2012's outbreak, between upwards of 153 children in the United States died from flu. A recent study further revealed more than 40 percent of the child flu fatalities between 2004 and 2012 were previously healthy children without any chronic medical conditions.

An estimated 165 children were killed from last year's flu season, while three children have died in the current 2013-2014 flu season, according to the CDCP.

The mandate wouldn't apply to family daycares, where someone supervises children in their own homes.

As currently written, the only exemptions to the new requirements would be medical, when a child develops rare side effects to the flu vaccine or has conditions that prevent him or her from receiving one, or religious, in which case a child's faith would have to be verified by a religious official.

The process to mandate flu vaccines for the city's young started when the health panel considered a preliminary proposal in September. The measure was then opened to public comment. Today's session will include a public hearing, during which the board will listen to opinions from the community before deciding whether to formally adopt the measure.

If the board supports the mandate, it would go into effect 30 after its formal approval.