Federal officials said Monday that if uninsured people don’t obtain coverage within the health law’s official enrollment period, which ends Jan. 31, they won’t get an extension to avoid the law’s penalty for going without insurance this time around. Earlier this year, the Obama administration offered uninsured people a reprieve if they missed the sign-up deadline for 2015 coverage, originally set at Feb. 15. People were given through April to sign up if they said they had learned about the penalty for going uninsured only when they filed their taxes.