NHS England and NHS Improvement have recently released updates on their guidance to managers regarding how to handle staff suffering from the now well recognised "Long COVID". This indicates that large numbers of NHS staff, currently 10% of the workforce, may be affected.
The guidance can be located on their website here.
This also clarifies how sickness absence and contractual sick pay should be handled. Note that it is NHSE&I's intention to review the guidance every 6 weeks, so it's worth regularly checking their website.