SARS-CoV-2 variants and associated symptoms, emergence periods, and vaccination
| Variant | Neurological symptoms | Vestibular symptoms | Othorhinolaryngologicalsymptoms | Vaccine introduction and effectiveness | Period of emergence |
|---|---|---|---|---|---|
| Alpha (B.1.1.7) | HeadacheBrain fog | Dizziness | Loss of taste/smellSore throat | December 2020 (first detected in the UK) | Vaccines were introduced in December 2020. Moderate reduction in neutralization for Moderna and Novavax vaccines compared to the original strain. |
| Beta (B.1.351) | HeadacheFatigueCognitive issues | Dizziness (rare) | Nasal congestionSore throat | Late 2020 (first detected in South Africa) | Pfizer vaccine showed reduced neutralization. Covaxin demonstrated significant neutralization. |
| Gamma (P.1) | AnxietyDepressionHeadache | Dizziness | Prolonged loss of taste/smellNasal congestion | Late 2020 (first detected in travelers from Brazil in Japan) | Reduced neutralization observed with Pfizer-BioNTech and Moderna vaccines. |
| Delta (B.1.617.2) | Severe headacheConfusion | Dizziness (rare) | Severe sore throatEar painReduced loss of smell | Late 2021 (first detected in India) | Pfizer and Moderna vaccines showed reduced immune response due to L452R mutation. Improved transmissibility linked to spike protein mutations. |
| Omicron (BA.1, BA.2, BA.4, BA.5) | Mental fatigueBrain fog | Dizziness (less common) | Predominant sore throatLess frequent loss of taste/smell | Late 2021 (first detected in multiple regions) | Vaccines and prior immunity appear to mitigate the severe effects. Less anosmia due to differences. In cellular tropism and reduced inflammatory dysregulation. |
| Omicron (XBB, BQ.1) | HeadacheBrain fogPeripheral neuropathy | Dizziness (less common) | Dominant nasal symptomsDry cough | Late 2022 (first detected in multiple regions) | Updated booster vaccines were introduced in mid-2022 to target Omicron subvariants. |