The head of Northamptonshire's Covid-19 vaccination rollout says a "safety net" is in place to prevent patients missing out on their second jabs.
Some concerns have been raised over second doses of the Pfizer-BioNTech vaccine being delayed.
But when asked if there are any issues with supplies of Pfizer doses in the county, programme director Chris Pallot said: "That is not correct.
"One practice put a statement on Facebook to say there was a supply issue with Pfizer and we had a very quick discussion with them and it was removed.
"Flow of Pfizer vaccine into the county has not been affected by any of the supply issues, that's only affecting AstraZeneca.
"My advice is if you're approaching the period of time when you're expecting to hear from your GP, at around week 11, and you've got any concern please call your practice.
"Please don't call any earlier because they are really busy and doing their best to call everyone.
"We will ensure there is a safety net in place for anyone who has not been able to attend their appointment for a second dose for whatever reason.
"There have been a couple of occasions where people haven't been called and we have put something in place.
Unless you call your practice we aren't going to know there's an issue. But please only do it when you're getting towards the end of that 12 week period."
More than 80,000 people have already received second doses of either Pfizer or AstraZeneca vaccines in Northamptonshire, according to Thursday's latest figures.
In excess of 350,000 have had at least one dose and are due their second shot within 12 weeks of the first, usually at the same location as the first — making a total of 431,699 doses delivered since the roll-out started in December.
Some confusion has been caused by the Moulton Park vaccination centre and GPs using different booking systems.
Those who receive jabs at the Moulton Park centre are given appointments for second visits at the same as their first while those contacted by their GPs get a follow-up appointment shortly before it is due, a maximum of 12 weeks after the initial dose.
Mr Pallot added: "If you attend the vaccination centre or a pharmacy, you'll be booked in for first and second jabs at the same time.
"Our GP colleagues can't do that, they don't have access to the national system so they have to manage it all through their own normal booking systems.
"It is understandable when some patients have their second appointments and others don't, they might think 'what's happening with me?' But all our GPs know how to access support if there's an issue with giving that appointment."