Overview

Since the first covid-19 vaccine was approved for use in the UK in December 2020, the aim of the covid-19 vaccination program has been, and continues to be, to reduce serious illness (hospitalization and death) in the population.

As the transition from pandemic response to pandemic recovery continues, the Joint Committee on Immunization and Immunization (JCVI) has begun considering the 2023 Covid-19 vaccine schedule. The current era of Omicron is characterized by:

• High population immunity achieved by vaccination and/or natural infection
• Lower disease severity compared to previous SARS-CoV-2 variants

At this time, the risk of severe COVID-19 is disproportionately increased among older age groups, elderly residents in care homes, and people with certain medical conditions. Compared to the early stages of the epidemic, much is now understood about SARS-CoV2 infection. However, there is ongoing uncertainty regarding virus evolution, the duration and extent of immunity, and the epidemiology of infection. These uncertainties limit the rapid development of a routine vaccination program against Covid-19.

Advice

JCVIProvisional advice for planning purposes prior to 2023 is as follows:

• In the year People exposed to severe COVID-19 in fall 2023 may receive an additional dose of vaccine to prepare for winter 2023 and 2024.

• In addition, a small group of people (such as the elderly and immunocompromised) may receive an additional booster dose in spring 2023.

• Emergency surgical vaccine responses may be required if a new strain with clinically significant biological differences compared to omicron differences emerges.

JCVI It also recommends the following:

• The 2021 booster offer (third dose) for people aged 16 to 49 years and not in the clinical risk group should close in line with the end of the fall 2022 vaccination campaign.^{[footnote 1]}

• Otherwise, healthy persons aged 5 to 49 years who develop a new medical condition in 2023 and are in a clinical risk group will be offered primary vaccination and/or booster vaccination during the next periodic vaccination campaign, as appropriate. Vaccinations outside these campaign periods are taken by individual clinical decisions

• A first-line Covid-19 vaccine should move towards targeted delivery during vaccination campaigns to protect people at high risk of Covid-19 by 2023. This includes the following

  • Older adults and staff working in care homes Residents living in care homes
  • Front line health and social care workers
  • All adults over the age of 50
  • People aged 5 to 49 years as defined in the clinical risk group Green book
  • People between the ages of 12 and 49 who have family relationships with people who are immunocompromised
  • Caregivers aged 16 to 49, b Green book

• Research should be considered to inform the optimal timing of booster vaccinations to prevent severe COVID-19 (hospitalizations and deaths) for groups at different levels of clinical risk.

Assumptions

It is estimated that more than 97% of adults in England had antibodies to SARS-CoV-2 from either infection or vaccination by the end of August 2022 (Ref. 1). In Great Britain, 93 to 99 percent of children aged 12 to 15 years and 74 to 98 percent of children aged 8 to 11 years had antibodies against SARS-CoV-2 at the end of August 2022 (References 1 and 2). Innate immunity alone confers a good level of protection against severe COVID-19, while the combination of innate and vaccine-induced immunity (mixed immunity) is associated with high levels of protection (refs. 3, 4, and 5). Developed over the past 2 and a half years, this high level of robust public protection is being monitored regularly by the UK’s Health Safety Agency.UKHSA) public health monitoring programs.

Not all hospitalizations and deaths due to SARS-CoV-2 infection are vaccine-preventable events. Due to the high transmissibility of Omicron variant, people with asymptomatic or mildly symptomatic infection who require hospital care for non-Covid-19 reasons may be accidentally infected with SARS-CoV-2. Such hospitalizations cannot be prevented by the Covid-19 vaccine. Conversely, some very vulnerable people may develop severe COVID-19 despite vaccination. These people often have health problems that put them at greater risk of serious illness from other infections. In the United Kingdom during the Omicron era (up to week 43, 2022), the highest rate of hospitalization was consistently observed in people aged 75 and over, while infection (non-serious illness) was particularly high at all ages. Among young people (Refs. 6 and 7).

Updated estimates of the number needed to vaccinate (NV) to prevent one hospitalization in the Omicron era, 800 people aged 70 and older should be incentivized to prevent one hospitalization from Covid-19 by autumn 2022 (fourth dose). Related NV It is 8,000 for people aged 50 to 59 and 92,500 for people aged 40 to 49 who are not in the clinical risk group (Appendix 1).

in November 2021, JCVI Recommended intake for healthy adults aged 40 to 49 years Due to the epidemiology of the time. Omicron variant At the end of November 2021, the discount was extended to healthy individuals aged 16 to 39 as part of the emergency surgery response (see) JCVI Stay up-to-date on the Covid-19 vaccination advice for children and young people And UK Vaccine Response to Omicron Variation: JCVI Advice). As of April 2022, uptake of the first booster dose of the Covid-19 vaccine was less than 0.1% per week for all eligible persons under 50 years of age (Figure 62c in Ref. 8). Based on current data, opening up the booster (third dose) to these groups is considered of limited continued value and the impact on overall vaccination coverage is negligible.

From 2021, primary vaccination discounts will be widely available. Acceptance of these vaccine discounts has been seen in recent months across all age groups (Figure 62a in Ref. 8). Beginning in early 2022, less than 0.01% of eligible individuals over the age of 12 per week received their first dose of the Covid-19 vaccine. More targeted primary vaccination delivery during vaccination campaigns would allow these efforts to be more focused and use NHS resources more efficiently.

Although the Covid-19 vaccination program has been very successful overall, there are some socioeconomic and ethnic groups where vaccination coverage is low (Ref. 6). Addressing health inequalities is an important long-term endeavor for all UK immunization programmes. Building trust, and especially vaccine confidence, requires an investment of time, resources and people. Among those who say appropriate and adequate communication should be provided before changes in primary vaccination coverage are those who have not yet received the vaccine.

Future differences and their impact on epidemiology

As the virulence of any new emerging variant cannot be reliably predicted, rapid response measures may be required in the event of major changes in population immunity, including any new concern.

JCVI Keeps the epidemiology of Covid-19 under review and advises on surgical response as needed.

References

1. Office for National Statistics (ONS) Coronavirus (Covid-19) Latest Insights: Antibodies.

2. UK Health Protection Agency Unpublished data.

3. Prophylactic efficacy of early SARS-CoV-2 infection and hybrid immunity against Omicron infection and acute disease: a systematic review and meta-regression..

4. Risk of SARS-CoV-2 reinfection and covid-19 hospitalization in individuals with natural and hybrid immunity: a general population-based study in Sweden.

5. Prevention against Omicron (B.1.1.529) BA.2 reinfection in health care workers given primary Omicron BA.1 or pre-Omicron SARS-CoV-2 infection and without mRNA vaccine: a trial-negative case-control study.

6. National Flu and Covid-19 Surveillance Reports: 2022 to 2023 Season.

7. The coronavirus (Covid-19) in the UK dashboard.

8. National Flu and Covid-19 Surveillance Report: October 27, 2022 (Week 43).