Wrth argymell hyn, mae'r Cyd-bwyllgor wedi ystyried y data sydd ar gael yn y DU ac yn rhyngwladol, sy'n parhau i awgrymu mai pobl hŷn sy'n wynebu'r risg uchaf o gael clefydau difrifol os cânt eu heintio gan COVID-19. Mae'r Pwyllgor hefyd wedi nodi y dylid cynnig dos y gwanwyn tua 6 mis ar ôl y dos brechlyn diwethaf, er y caniateir hyblygrwydd gweithredol o ran yr amseriad.  Ystyrir mai'r brechlynnau COVID-19 amrywiolyn XBB diweddaraf, sy'n cyfateb agosaf at yr amrywiolion sy'n lledaenu ar hyn o bryd, sydd orau i'w defnyddio ar gyfer yr ymgyrch.  Dyma'r brechlynnau Pfizer-BioNTech a Moderna mRNA XBB.1.5.
In making this recommendation, the JCVI has considered available data from the UK and internationally, which continues to suggest older people are at the highest risk of experiencing severe disease if infected by COVID-19. The Committee has also stated that the spring dose should be offered around 6 months after the last vaccine dose, although operational flexibility around the timing is allowed.  The latest COVID-19 XBB-variant vaccines, which most closely match currently circulating variants, are considered preferable for use in the campaign.  These are the Pfizer-BioNTech and Moderna mRNA XBB.1.5 vaccines.