JCVI has considered a number of different vaccination strategies, including those targeting transmission and those targeted at providing direct protection to persons most at risk.
In order to interrupt transmission, mathematical modelling indicates that we would need to vaccinate a large proportion of the population with a vaccine which is highly effective at preventing infection (transmission). At the start of the vaccination programme, good evidence on the effects of vaccination on transmission will not be available, and vaccine availability will be more limited. The best use of available vaccine will also, in part, be dependent on the point in the pandemic the UK is at.
Given the current epidemiological situation in the UK, the best option for preventing morbidity and mortality in the initial phase of the programme is to directly protect persons most at risk of morbidity and mortality.
Age
Current evidence strongly indicates that the single greatest risk of mortality from COVID-19 is increasing age and that the risk increases exponentially with age. Mathematical modelling indicates that the optimal strategy for minimising future deaths or quality adjusted life year (QALY) losses is to offer vaccination to older age groups first. These models assume an available vaccine is both safe and effective in older adults. Data also indicates that the absolute risk of mortality is higher in those over 65 years than that seen in the majority of younger adults with an underlying health condition (see below). Accordingly, the committee’s advice largely prioritises based on age.
Age-based programmes are usually easier to implement and therefore achieve higher vaccine uptake. An age-based programme is also likely to increase uptake in those with clinical risk factors as the prevalence of these increases with age.
Older adults resident in care homes
There is clear evidence that those living in residential care homes for older adults have been disproportionately affected by COVID-19 as they have had a high risk of exposure to infection and are at higher clinical risk of severe disease and mortality. Given the increased risk of outbreaks, morbidity and mortality in these closed settings, these adults are considered to be at very high risk. The committee’s advice is that this group should be the highest priority for vaccination. Vaccination of residents and staff at the same time is considered to be a highly efficient strategy within a mass vaccination programme with the greatest potential impact (see below).
Health and social care workers
Frontline health and social care workers are at increased personal risk of exposure to infection with COVID-19 and of transmitting that infection to susceptible and vulnerable patients in health and social care settings. The committee considers frontline health and social care workers who provide care to vulnerable people a high priority for vaccination. Protecting them protects the health and social care service and recognises the risks that they face in this service. Even a small reduction in transmission arising from vaccination would add to the benefits of vaccinating this population, by reducing transmission from health and social care workers to multiple vulnerable patients and other staff members. This group includes those working in hospice care and those working temporarily in the COVID-19 vaccination programme who provide face-to-face clinical care.
There is evidence that infection rates are higher in residential care home staff than in those providing domiciliary care or in healthcare workers. Care home workers are therefore considered a very high priority for vaccination.
Prioritisation among health and social care workers
Frontline health and social care workers at high risk of acquiring infection, at high individual risk of developing serious disease, or at risk of transmitting infection to multiple vulnerable persons or other staff in a healthcare environment, are considered of higher priority for vaccination than those at lower risk. This prioritisation should be taken into account during vaccine deployment.
Clinically extremely vulnerable (shielding patients)
Individuals considered extremely clinically vulnerable have been shielding for much of the pandemic. This means that available data is likely to underestimate the risk in this group. Many of those who are clinically extremely vulnerable are in the oldest age groups and will be among the first to receive vaccine. Considering data from the first wave in the UK, the overall risk of mortality for clinically extremely vulnerable younger adults is estimated to be roughly the same as the risk to persons aged 70 to 74 years. Given the level of risk seen in this group as a whole, JCVI advises that persons aged less than 70 years who are clinically extremely vulnerable should be offered vaccine alongside those aged 70 to 74 years of age. There are 2 key exceptions to this, pregnant women with heart disease and children (see below).
Many individuals who are clinically extremely vulnerable will have some degree of immunosuppression or be immunocompromised and may not respond as well to the vaccine. Therefore, those who are clinically extremely vulnerable should continue to follow government advice on reducing their risk of infection. Consideration has been given to vaccination of household contacts of immunosuppressed individuals. However, at this time there is no data on the size of the effect of COVID-19 vaccines on transmission. Evidence is expected to accrue during the course of the vaccine programme, and until that time the committee is not in a position to advise vaccination solely on the basis of indirect protection. Once sufficient evidence becomes available the committee will consider options for a cocooning strategy for immunosuppressed individuals, including whether any specific vaccine is preferred in this population.
Persons with underlying health conditions
There is good evidence that certain underlying health conditions increase the risk of morbidity and mortality from COVID-19. When compared to persons without underlying health conditions, the absolute increased risk in those with underlying health conditions is considered generally to be lower than the increased risk in persons over the age of 65 years (with the exception of the clinically extremely vulnerable – see above). The committee’s advice is to offer vaccination to those aged 65 years and over followed by those in clinical risk groups aged 16 years and over. The main risk groups identified by the committee are set out below:
- chronic respiratory disease, including chronic obstructive pulmonary disease (COPD), cystic fibrosis and
- severe asthma
- chronic heart disease (and vascular disease)
- chronic kidney disease
- chronic liver disease
- chronic neurological disease including epilepsy
- Down’s syndrome
- severe and profound learning disability
- diabetes
- solid organ, bone marrow and stem cell transplant recipients
- people with specific cancers
- immunosuppression due to disease or treatment
- asplenia and splenic dysfunction
- morbid obesity
- severe mental illness
Other groups at higher risk, including those who are in receipt of a carer’s allowance, or those who are the main carer of an elderly or disabled person whose welfare may be at risk if the carer falls ill, should also be offered vaccination alongside these groups.