I assume it's the Mirror:
The vaccine priority queue ranked:
- Residents and staff in a care home for older adults
- All those 80 years of age and over and health and social care workers
- All those 75 years of age and over
- All those 70 years of age and over and clinically extremely vulnerable individuals (not including pregnant women and those under 18 years of age)
- All those 65 years of age and over
- Adults aged 18 to 65 years in an at-risk group *
- All those 60 years of age and over
- All those 55 years of age and over
- All those 50 years of age and over
So morbid obesity is influenced in priority group 6 which includes :
Chronic respiratory disease
Chronic heart disease and vascular disease
Chronic kidney disease
Chronic liver disease
Chronic neurological disease
Diabetes
Immunosuppression
Asplenia or dysfunction of the spleen
Morbid obesity
Severe mental illness
Adult carers
Adult household members, close contacts and carers of immunocompromised adults (i.e. individuals who expect to share living accommodation on most days, or those providing regular care, where continuing close contact is unavoidable).
Younger adults in long-stay nursing and residential care settings.
But the headline is 'Severely obese to get vaccine before fit and healthy over-60s, guidance confirms' because? Clickbait? Headline could just as easily be 'People with Chronic heart disease and vascular disease to get vaccine before fit and healthy over-60s, guidance confirms' but I guess that wouldn't get as many clicks? 
www.mirror.co.uk/news/uk-news/severely-obese-vaccine-before-fit-23081571
“The JCVI’s interim advice on COVID-19 vaccine prioritisation was developed with the aim of preventing as many deaths as possible.
“The evidence shows that at-risk groups – including people with a BMI of over 40 – have an overall higher risk of death from COVID-19 than those without underlying health conditions.”
So, seems reasonable to do it that way.