2. Current German Recommendations

2.

The updated recommendations include the introduction of a new booster for specific population groups who received their last vaccination booster or had an infection 12 months ago or longer. The targeted groups are as follows:

(1) 

Individuals aged ≥60 years;

(2)

 Residents in nursing homes;

(3)

 HCPs who have direct contact with patients and/or nursing home residents;

(4) 

All individuals aged ≥6 months with underlying diseases, encompassing bedridden conditions, chronic obstructive lung disease (COPD), chronic cardiovascular, hepatic and renal diseases, diabetes mellitus and other metabolic diseases, obesity, chronic neurological diseases (e.g., dementia, stroke, mental retardation, psychological diseases), immunodeficiency (e.g., human immunodeficiency virus [HIV] infection, chronic inflammatory diseases under immunosuppressive therapy including post-organ transplantation), and active cancer;

(5)

 Family members and individuals with direct contact with immunocompromised persons (e.g., after organ or stem cell transplantation, haemodialysis) aged ≥6 months.

3.

The administration timing of the “yearly” booster is recommended during the autumn, aligning with statistical evidence indicating that disease waves tend to peak during the winter months. This strategic timing aims to maximise the effectiveness of the booster in preparation for the seasonal increase in COVID-19 cases. Additionally, it is suggested that, when indicated, the COVID-19 booster may be administered concurrently with the influenza or pneumococcal vaccine. This co-administration approach aims to optimise protection aims to optimise protection against both COVID-19 and influenza or pneumonia, particularly during periods of heightened respiratory pathogen activity, i.e., in the winter.

4.

The choice of vaccine for the booster is recommended to be adapted to the prevalent viral variants in the region. The current variant in Germany is XBB.1.5 (as of 11.01.2024). In European Union (EU) countries, including Germany, the approved booster vaccines encompass various categories:

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(monovalent) mRNA vaccines: Comirnaty Original and Comirnaty XBB.1.5 (BioNTech/Pfizer), Spikevax (Moderna; cautioned against use as a booster for individuals aged between 6 months and 5 years), and Spikevax XBB.1.5 (Moderna).

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bivalent mRNA vaccines: Comirnaty Original/Omicron BA.4/5 and Comirnaty Original/Omicron BA.1 (BioNTech/Pfizer), Spikevax bivalent Original/Omicron BA.4/5 and Spikevax bivalent Original/Omicron BA.1 (Moderna). Notably, Moderna vaccines should be administered carefully to individuals aged < 30 years due to the risk of peri- and myocarditis.

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viral vector vaccines: Vaxzevria (AstraZeneca) and JCOVDEN (Janssen Cilag International), recommended only for individuals aged ≥60 years due to the risk of thromboembolic events in younger individuals. Moreover, JCOVDEN must not be used as a booster in individuals who previously received mRNA or viral vector vaccines.

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protein-based vaccines: Nuvaxovid (only for individuals aged ≥18 years) and Novaxovid XBB 1.5 (Novavax), seemingly suitable for young individuals due to the very low risk of peri- and myocarditis. However, there are limited scientific data on the use of these vaccines in pregnant and breastfeeding women.

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inactivated whole-virus vaccine: COVID-19 vaccine Valneva (Valneva) is recommended only for individuals with contraindications to other vaccines and unsuitable for those who have already received Valneva or viral vector vaccines as part of their basic immunisation. Limited scientific data are available regarding the use of this vaccine in pregnant and breastfeeding women.

5.

Pre-exposure prophylaxis (PEP) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is designed to complement vaccination and hygiene practices, not replace them. In specific cases, such as after stem cell transplantation (prior to immunological reconstitution), B-cell depletion therapies (when B-cell reconstitution is absent), CAR-T-cell therapies, severe immunosuppression (e.g., after solid organ transplantation or ongoing chemotherapy), and those with genetically-related immune defects leading to poor antiviral immunity, the use of Evusheld (AstraZeneca) may be considered. This agent comprises two monoclonal Ab, namely, tixagevimab and cilgavimab. However, it is crucial to note that the efficacy of this drug preparation is significantly reduced or non-existent against the currently circulating Omicron sublineages.

6.

According to Section 22a of the German Infection Protection Law, foreign nationals residing in EU countries who have been vaccinated with vaccines not approved by the EU, such as Sinovac (Sinovac Biotech Ltd. SVA:NASDAQ GS, Beijing, China), Sinopharm (China National Pharmaceutical Group Co., Beijing, China), COVAXIN, (Bharat Biotech International Ltd., Turkapally, India), and Sputnik V (Russian Gamaleya Research Institute of Epidemiology and Microbiology), are required to repeat the EU-approved vaccination ^[2], even though some investigators found that the Sinopharm booster is safe and capable of rescuing immune signals and further strengthening the protective immune response by increasing nAb levels against some Omicron sublineages ^[7][9].