"I read its something to do with the fact they haven't approved the Oxford vaccine".
Not so, its all to do now with delta variant concerns. That is the stumbling block here. The United States government is not planning to remove the current entry ban for travellers from the 26 Schengen Area Member States, Ireland, the UK, China, India, South Africa, Iran and Brazil, at least for now.
Sources within the White House have confirmed for Reuters that “at this point”, the US authorities do not intend to lift any of the entry restrictions for arrivals from the abovementioned due to the concerns raised from the spread of the Delta variant in these countries.
Sadly my guess is that not much change will occur until late this year or even early next year.
The AstraZeneca COVID-19 vaccine is not yet approved in the United States because the FDA has asked AstraZeneca to show results from a large-scale trial. The FDA asked the company to conduct a larger trial in order to get clearer data than they gathered in their first rounds of testing. In the first trials in the U.K., some participants unexpectedly received half-doses of the first shot in the vaccine, and the early trials did not include enough people older than 65, reports the Washington Post.