GPs and patients frustrated by a shortage of the new flu vaccine for over-65s are being told the final delivery batch will arrive by Saturday.
NHS England said there would be enough vaccines for everyone to be protected ahead of winter.
But doctors' leaders said more guidance should have been given to GPs and patients to avoid disruption over the phased delivery of supplies.
Older adults are advised to get the flu jab by early December.
This gives time for protection before flu starts to circulate, normally later in the month.
However, the staggered delivery of supplies of the over-65s vaccine from the manufacturer Seqirus to GPs and pharmacies means some older patients have not been able to be vaccinated.
In a survey of 650 GPs in Pulse, nearly 70% said there had been a shortage of this flu vaccine at their practice.
That meant they could not vaccinate as many elderly patients as they would have liked.
Some GPs said they had to cancel appointments while others said it had created staffing problems.
But a spokesperson for NHS England said that this week, "100% of vaccines will have been delivered by the manufacturer to those surgeries and pharmacists who placed an order on time".
"So the public can be assured that there is sufficient supply of the vaccine in stock for everyone to get protected ahead of winter."
Dr Richard Vautrey, chairman of the GP committee at the British Medical Association (BMA), said it had not been an easy time for GPs.
"As practices begin planning for next year, NHS England must learn lessons from the disruption seen in the past weeks.
"Adequate notice and guidance to all practices must be given well in advance of the ordering period, to allow both practices and manufacturers to ensure there are no further supply problems for next year.
"Improving information for the public would also be beneficial," he said.
'Best defence against flu'
Public Health England said the adjuvanted flu vaccine, which is designed to help the immune systems of older people fight off flu, was worth having.
Dr Mary Ramsay, head of immunisations at PHE, said: "We encourage all older adults to get an appointment with their GP or pharmacist by early December before flu typically starts to circulate later in the month.
"However, it's always worth getting vaccinated even if it's later in winter – it's the best defence we have against an unpredictable virus."
The new flu vaccine is also available to over-65s in Wales and Northern Ireland.
In Scotland, it is only available to the over-75s.