COVID-19 transmission in the EU/EEA, SARS-CoV-2 variants, and public health considerations for Autumn 2023


Public health actions 

Monitoring and reporting 

Current data availability makes it challenging to assess the COVID-19 epidemiological situation in the EU/EEA. Although some countries have continued with primary care syndromic surveillance this summer, the low levels of testing in these settings add substantial uncertainty to estimates of SARS-CoV-2 positivity. SARI surveillance has been expanded in the EU/EEA but is still limited to relatively few countries. As of week 34, only one third of the countries reported data on admissions to hospital or ICU, and around half reported data on COVID-19 deaths. These figures can still be a useful complement to data from sentinel systems, but must be treated with some caution. The lack of a standardised case definition in respiratory infections’ syndromic surveillance systems across countries and potential for changes in underlying strategies for testing and reporting can introduce bias or artefact. The reduction in PCR testing and low levels of transmission over the summer has also led to very limited volumes of sequencing, which limits ECDC’s ability to assess variants. 

As outlined in the guidance document, ‘Operational considerations for respiratory virus surveillance in Europe’ [1], EU/EEA Member States are encouraged to expand their use of, and report data from well-designed, representative population-based surveillance in primary and secondary care to monitor trends in transmission and severe disease. Where possible, all SARS-CoV-2-positive specimens from representative surveillance systems should be sequenced and reported to GISAID and/or TESSy to facilitate the assessment of circulating variants.

Vaccination

Based on ECDC’s interim public health considerations for COVID-19 vaccination roll-out during 2023, vaccination efforts should focus on protecting those aged over 60 years and other vulnerable individuals irrespective of age (such as those individuals with underlying comorbidities and individuals with immunocompromised conditions). In addition, mathematical modelling indicated that an autumn 2023 vaccination campaign (with an optimistic scenario of high vaccine uptake among individuals aged 60 years and above) is expected to prevent an estimated 21–32% of the cumulative total all-age COVID-19 related hospitalisations across EU/EEA countries until 28 February 2024 [13].

In the EU/EEA, the COVID-19 vaccine uptake has been monitored since the start of the vaccination campaign in December 2020 [14]. As of August 2023, 84.9% (range: 13.6–100%) of the population aged 60 years and above (60+) in EU/EEA countries has received a first booster dose (with differences of uptake across countries), with the majority of countries (n=17) reporting national uptakes above 80% in this age group. For the second booster dose, 35.6% (range: 0.4–87.1%) of the population aged 60 years and above has received a second booster dose, with most countries (n=20) reporting national uptakes below 50% in this age group. In the EU/EEA, based on 23 countries reporting, 4% (range: <0.1–47.2%) of the population aged 60 years and above has received a third booster dose, with all countries reporting an uptake of below 50% in this age group. Overall, the vaccine uptake of the first booster dose levelled off in autumn 2021 and is very high in the EU/EEA, with the majority of countries reporting vaccine uptakes over 80% for the first booster dose. However, this situation differs for the second booster dose, with the majority of countries still not reaching 50% of vaccine uptake in this age group. 

Several EU/EEA countries have published their recommendations for COVID-19 autumn vaccination campaigns. The age cut-offs indicated differ between countries. In some countries, vaccination is recommended to the same age group as the annual influenza vaccination. Other high-risk groups recommended vaccination include persons aged six months and older with underlying diseases (i.e. chronic respiratory, cardiovascular, liver and kidney disease, diabetes, obesity, chronic neurological disease, immunosuppression) and residents in long-term care facilities.

On 30 August 2023, EMA’s human medicines committee (CHMP) recommended authorising an adapted Comirnaty vaccine targeting the Omicron XBB.1.5 subvariant [15]. According to the recommendation for authorisation, adults and children aged from five years who require vaccination should have a single dose, irrespective of their COVID-19 vaccination history. Children aged between six months and four years who require vaccination may have one or three doses depending on whether they have completed a primary vaccination course or have had COVID-19. The European Commission authorised the Comirnaty XBB.1.5-adapted COVID-19 vaccine on 1 September 2023 [16].

In the current setting, countries should carefully consider factors that have previously limited booster vaccine uptake and address them as we approach autumn vaccination campaigns. So that vaccination campaigns adequately protect population groups that remain at risk of severe COVID-19 disease, countries should assess their readiness to detect and respond to epidemiological signals of increased COVID-19 transmission. Due to the evolving COVID-19 epidemiology in the EU/EEA, the timely identification of vaccination campaign target groups is essential to protect people at a high risk for severe disease and death. Communication campaigns providing clear information through trusted channels and messengers regarding which groups vaccination is recommended to, why vaccination is important, and the timing of them are all key to improving vaccine uptake [13]. This should include engagement with healthcare workers, as they are trusted sources regarding information on vaccination. Strategies to facilitate access to vaccination services should also be considered.

Consulted experts (in alphabetical order)

Ana Torres, Jordi Borrell Pique, Orlando Cenciarelli, Luca Freschi, Kate Olsson, Ajibola Omokanye, Theodora Stavrou, Andrea Würz.

References

1.    European Centre for Disease Prevention and Control (ECDC). Country overview report: week 34 2023. Stockholm: ECDC; 2023. Available at: https://covid19-country-overviews.ecdc.europa.eu/index.html

2.    Tamura T, Ito J, Uriu K, Zahradnik J, Kida I, Anraku Y, et al. Virological characteristics of the SARS-CoV-2 XBB variant derived from recombination of two Omicron subvariants. Nature communications. 2023;14(1):2800. Available at: https://www.nature.com/articles/s41467-023-38435-3

3.    Github. CoV-lineages/pango-designation. 2023. Available at: https://github.com/cov-lineages/pango-designation

4.    European Centre for Disease Prevention and Control (ECDC). SARS-CoV-2 variants of concern as of 10 August 2023. Stockholm: ECDC; 2023. Available at: https://www.ecdc.europa.eu/en/covid-19/variants-concern

5.    European Centre for Disease Prevention and Control (ECDC). ECDC SARS-CoV-2 variant classification criteria and recommended EU/EEA Member State actions. Stockholm: ECDC; 2023. Available at: https://www.ecdc.europa.eu/sites/default/files/documents/ECDC%20SARS-CoV-2%20variant%20classification%20criteria%20and%20recommended%20Member%20State%20actions.pdf

6.    Ayijiang Y, Weiliang S, Jing W, Fanchong J, Yuanling Y, Xiaosu C, et al. Repeated Omicron exposures override ancestral SARS-CoV-2 immune imprinting. bioRxiv [Preprint]. 2023. DOI: 10.1101/2023.05.01.538516. Available at: https://www.biorxiv.org/content/10.1101/2023.05.01.538516v4

7.    Chaguza C, Hahn AM, Petrone ME, Zhou S, Ferguson D, Breban MI, et al. Accelerated SARS-CoV-2 intrahost evolution leading to distinct genotypes during chronic infection. Cell Reports Medicine. 2023;4(2) Available at: https://www.cell.com/cell-reports-medicine/pdf/S2666-3791(23)00035-6.pdf

8.    Raglow Z, Surie D, Chappell JD, Zhu Y, Martin ET, Kwon JH, et al. SARS-CoV-2 shedding and evolution in immunocompromised hosts during the Omicron period: a multicenter prospective analysis. medRxiv [Preprint]. 2023. DOI: 2023.08.22.23294416. Available at: https://www.medrxiv.org/content/10.1101/2023.08.22.23294416.abstract

9.    Nextstrain.org. Phylogenetic analysis of BA.2.86 diversity. 2023. Available at: https://nextstrain.org/groups/neherlab/ncov/BA.2.86?m=num_date

10.   EVEscape. Biweekly Variant Report 25/08/2023. Emerging variant BA.2.86 predicted to have significant antibody escape with up to 21- and 26-fold decrease in neutralizing titers relative to CH.1.1 and XBB.1.5, respectively. Available at: https://evescape.org/data

11.   Yang S, Yu Y, Jian F, Song W, Yisimayi A, Chen X, et al. Antigenicity and infectivity characterization of SARS-CoV-2 BA.2.86. bioRxiv [Preprint]. 2023. DOI: 10.1101/2023.09.01.555815. Available at: https://www.biorxiv.org/content/biorxiv/early/2023/09/04/2023.09.01.555815.full.pdf

12.   Sheward DJ, Yang Y, Westerberg M, Öling S, Muschiol S, Sato K, et al. Sensitivity of BA.2.86 to prevailing neutralising antibody responses. bioRxiv [Preprint]. 2023. DOI: 10.1101/2023.09.02.556033. Available at: https://www.biorxiv.org/content/biorxiv/early/2023/09/04/2023.09.02.556033.full.pdf

13.   European Centre for Disease Prevention and Control (ECDC). Interim public health considerations for COVID-19 vaccination roll-out during 2023. Stockholm: ECDC; 2023. Available at: https://www.ecdc.europa.eu/en/publications-data/interim-public-health-considerations-covid-19-vaccination-roll-out-during-2023

14.   European Centre for Disease Prevention and Control (ECDC). COVID-19 Vaccine Tracker. Stockholm: ECDC; 2023. Available at: https://vaccinetracker.ecdc.europa.eu/public/extensions/COVID-19/vaccine-tracker.html#summary-tab

15.   European Medicines Agency (EMA). Comirnaty: EMA recommends approval of adapted COVID-19 vaccine targeting Omicron XBB.1.5. Amsterdam: EMA; 2023. Available at: https://www.ema.europa.eu/en/news/comirnaty-ema-recommends-approval-adapted-covid-19-vaccine-targeting-omicron-xbb15

16.   European Commission (EC). COVID-19: Commission authorises adapted COVID-19 vaccine for Member States’ autumn vaccination campaig. Brussels: EC; 2023. Available at: https://ec.europa.eu/commission/presscorner/detail/en/ip_23_4301



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