The latest Covid 19 vaccine introduced in September 2023 has a very low uptake in the US, at about 18%. The JN.1 Covid variant is for which this vaccine is effective is now making up about 50% of the cases of Covid in the US. It was at 7% in November. It is very transmissable and masks are now advised.The Covid related hospitalizations are up 10% to 26,000 in the fourth week of December. Symptoms of this variant are cough, fever, body aches, and fatigue that last for 3-4 days, says this NYT report.