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Demand for COVID-19 booster shots in California has been slower than some health officials anticipated, according to data obtained by The Times, sparking new concerns of at-risk populations losing immunity as the risky holiday season approaches.

The alarm is particularly high for elderly people and those with compromised immune systems, groups who have the highest risk of suffering severe consequences or death from breakthrough inflections. Officials are also strongly recommending that all recipients of the Johnson & Johnson vaccine get a booster shot.

Numbers from the California Department of Public Health show that initial demand for booster shots has been much lower than originally expected. After federal officials enthusiastically urged some recipients of the Pfizer-BioNTech vaccinations to get booster shots, California authorities anticipated demand would peak the first full week of October.

But only 230,000 booster shots were administered to seniors that week, just 21% of the projected demand of 1.1 million. And for adults under 65, just 450,000 booster doses were administered that week — just 17% of the expected demand of 2.7 million.

Read the full story on LATimes.com.