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Under-18s’ Covid jab interval could be shortened if new variant sparks ‘concern’

booster 16-17 jab

Healthy under-18s could see a shorter interval between their first and second Covid jabs if a new variant sparks ‘concern’ about vaccine effectiveness, new guidance has said.

In an update to the national protocol for the Pfizer vaccine – which is recommended for under-18s – the UK Health Security Agency (UKHSA) said that ‘periods of high incidence’ or concerns over vaccine effectiveness could trigger a reduction in the interval between doses.

The document, updated this week, said: ‘For those under 18 years who are not in a high-risk group, a 12-week interval is preferred.

‘This is based on precautionary advice from the JCVI based on emerging evidence of a lower rate of myocarditis in countries that use schedules of eight to 12 weeks.’

However, it added: ‘The interval may be shortened to eight weeks in periods of high incidence or where there is concern about vaccine effectiveness (for example a new variant).’

The ‘timing of any change will be advised by JCVI or UKHSA and published in operational guidance agreed by DHSC and NHSEI’, it said.

Previous guidance said that 16- and 17-year-olds should book their second jab 12 weeks after the first and vaccination should be delayed for 12 weeks following a positive Covid test result in 12-17s.

The updated advice was based on emerging evidence from the UK and other countries that leaving a longer gap may further reduce the already small risk of myocarditis.

Meanwhile, the document also said that a booster dose of the Pfizer Covid vaccine can now be given to immunosuppressed individuals from 16 years of age.

It also extended the frozen vaccine’s shelf-life from six to nine months.

The protocol said:

  • Frozen vials can be stored for nine months at -90C to -60C and within this shelf-life, unopened vials may be stored and transported at -25C to -15C ‘for a single period of up to two weeks’
  • They can then be returned to -90C to -60C
  • Thawed unopened vials have a one-month shelf-life at 2C to 8C and up to 12 hours can be used for transportation within this
  • Before use, the unopened vials can be stored for ‘up to two hours at temperatures up to 30C’ but the vaccine cannot be re-frozen once thawed

The JCVI last month recommended that the Covid booster jab campaign should be expanded to all over-18s in response to the Omicron variant.

It also recommended that a booster dose can be given three months after completion of the initial course of vaccination – a reduction from previous guidance of six months.

Further, 12 to 15-year-olds should have their second dose of Covid vaccine 12 weeks after their first dose, the JCVI added.

And patients who are immunosuppressed should be offered a booster dose, three months after their third jab, which had completed their initial vaccination course.

It comes as the UK medicines regulator has given a ‘clear steer’ that the requirement to keep patients for a 15-minute observation after mRNA Covid vaccination – including the Pfizer jab – is not being relaxed ‘at this time’.

And new Government guidance has said that GPs and practice staff are not exempt from self-isolation if they are a close contact of a ‘suspected or confirmed’ Omicron Covid case.

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