Coronavirus (COVID-19): state of the epidemic - 13 May 2022

Looking ahead

New Variants

VOC-22JAN-01 (Omicron sub-lineage BA.2) remains dominant in the United Kingdom (UK) and Scotland based on sequencing data. There is some diversity developing within this variant. V-22APR-03 (Omicron sub-lineage BA.4) and V-22APR-04 (Omicron sub-lineage BA.5) are increasing in South Africa and may be associated with the current increase in incidence there. Small numbers of BA.4 and BA.5 sequences continue to be detected in the UK^{[68] [69]}. There is evidence of a growth advantage of BA.4 and BA.5 compared to BA.2, in South Africa; however, it is not clear whether the growth advantage of BA.4 and BA.5 will be seen elsewhere. There is evidence of some antigenic change of BA.4 and BA.5 compared to BA.2 based on structural modelling and lab based pseudo-virus neutralisation studies. There is currently insufficient data to draw conclusions on the disease severity of BA.4 and BA.5^[70].

Scottish Contact Survey

Changes in patterns of mixing will likely impact on future Covid-19 prevalence. The Scottish Contact Survey measures the times and settings in which people mix where they could potentially spread Covid-19^[71]. Average contacts from the most recent wave of the Scottish Contact Survey (28 April to 4 May) indicate an average of 4.9 contacts. This has remained at a similar level compared to the previous wave of the survey (14 April to 20 April).

Mean contacts within the work setting have increased in the last two weeks by 34% whereas contacts within the home and other setting (contacts outside home, school and work) have decreased by 7% and 21% respectively over the same period.

The youngest age group (18 to 29 year olds) reported a decrease in contacts within the last two weeks, by approximately 57%. The decrease is largely driven by a reduction in contacts within the other setting.

Modelling the Epidemic

The Scottish Government assesses the potential impact of Covid-19 on the NHS in the next few weeks. The latest Modelling the Epidemic report includes infection and hospital bed projections over the next six weeks. These projections include the effect of vaccines rolled out so far and projected future vaccine rollout including the rollout of fourth doses, and the effect of the end of the legal requirement for wearing face masks on 18 April 2022. The changes to restrictions are assumed to result in people’s behaviour gradually returning towards pre-pandemic levels over the coming weeks and months. The ‘Central’ scenario assumes that transmissibility remains at current levels. ‘Worse’ assumes a higher transmissibility for Covid-19 whereas ‘Better’ assumes a lower transmissibility.

According to the Scottish Government modelling based on wastewater derived data, it is estimated that daily infections may be up to 100,000 in mid-June^[72]. The increase seen in projected infections is a result of waning immunity and gradual changes in behaviour due to the lifting of restrictions. The projections for this period are therefore even more uncertain than usual^[73].

Figure 11 shows the impact of the daily infection projections on the number of people in hospital. The modelling includes all hospital stays, whereas the actuals only include stays up to 28 days’ duration that are linked to Covid-19. It is estimated that hospital occupancy may be up to 1,250 in mid-June. However, there continues to be uncertainty over hospital occupancy and intensive care in the next six weeks^[74].

Long Covid-19

According to the Office for National Statistic (ONS), long Covid is defined as symptoms persisting more than four weeks after the first suspected coronavirus (Covid-19) episode that are not explained by something else.

The ONS Covid-19 Infection Survey estimated that around 1,795,000 million people (95% confidence interval: 1,751,000 to 1,839,000) in the private residential population in the UK (2.78% of the respective population; 95% CI: 2.71% to 2.84%) reported experiencing long Covid over the four-week period ending 3 April 2022. In Scotland, over the same period, an estimated 151,000 people (95% CI: 139,000 to 164,000) in the private residential population (2.88% of the respective population; 95% CI: 2.64% to 3.11%) reported experiencing long Covid of any duration. This compares to:

• 2.78% in England (95% CI: 2.71% to 2.85%),
• 2.81% in Wales (95% CI: 2.51% to 3.11%), and
• 2.30% in Northern Ireland (95% CI: 1.96% to 2.64%)^[75].

Fortnightly modelled estimates for Scotland are also usually published in the Modelling the Epidemic report. However, a report on the rate of long Covid-19 has not been included this week. This will resume again once updated estimates of self-reported long Covid-19 prevalence amongst those infected with the less severe Omicron variant become available.