AHE BB

Generally, BA.4 and BA.5 variants cause mild disease but spread in large numbers potentially because, unlike the Wuhan strain, which settles in the lungs, these newer strains seem to attach to the more benign upper nasal passages. As with other Omicron variants, BA.4 and BA.5 symptoms are generally mild, and may include fever, malaise, and loss of smell, although the prevalence of long-term symptoms (long COVID) is still being evaluated. Serious illness is rare but possible, especially in the unvaccinated.