Washington, June 7 : More than 300 million coronavirus vaccine shots have been administered in the US so far, according to figures from the country's Centers for Disease Control and Prevention (CDC). Some 63.5 per cent of all adults in the country have received at least a first dose of coronavirus vaccine while over 52 per cent of over 18s are already fully vaccinated, dpa news agency reported citing the latest CDC figures which were publised on Sunday. President Joe Biden in May said his administration aimed for 70 per cent of adults to have received at least one dose of a Covid-19 vaccine by July 4, when Independence Day is celebrated. Among the higher-risk group of those aged 65 and older, 86.3 per cent have had a first dose and 75.5 per cent are fully vaccinated. Since the start of the vaccine drive in December 2020, a total of over 301 million doses have been administered in the US, which has a population of 330 million. A nurse received the country's first jab in New York on December 14, 2020. The US is largely using Moderna and Pfizer vaccines, which require two doses to be fully effective. The single-shot Johnson & Johnson vaccine is also in use in the country. /IANS