California, the most populous state in the US, has opened up Covid-19 vaccination appointments to everyone aged 16 and above."Safe, free, and effective Covid-19 vaccines are now available to everyone age 16 and up," the latest version of the state's inoculation scheduling tool My Turn said on Thursday."Let's end this pandemic," said California public health officials on the page, urging residents to check for available appointments and book their vaccination as soon as possible.Governor Gavin Newsom said on Thursday morning that nearly 50 percent of eligible residents of the state have been vaccinated so far."We've administered 24 million doses, over 8 million more than any other state. We have the lowest positivity rate in the country," he added.The state, home to around 40 million residents, had expanded vaccine eligibility to people aged 50 and older, starting April 1.California paused the use of Johnson & Johnson Covid-19 vaccine in accordance with recommendations from two federal health agencies on Tuesday.State officials noted that the move would not significantly impact, since in the state less than 4 per cent of vaccine allocation this week involves the Johnson & Johnson vaccine.California is one of the hardest-hit states in the country.It has seen more than 3.6 million cases and 59,000 deaths from the pandemic, both the highest in the country so far.New Covid-19 cases, deaths and hospitalisations have continued to decline in recent weeks.Newsom announced earlier this month that the state plans to fully reopen by June 15, if vaccinations remain widely available and hospitalisations associated with the virus stay low.