Abstract
There has been an important change in the clinical characteristics and
immune profile of COVID-19 patients during the pandemic thanks to the
extensive vaccination programs. Here, we highlight recent studies on
COVID-19, from the clinical and immunological characteristics to the
protective and risk factors for severity and mortality of COVID-19. The
efficacy COVID-19 vaccines and potential allergic reactions after
administration are also discussed. The occurrence of new variants of
concerns such as Omicron BA.2, BA.4 and BA.5 and the global
administration of COVID-19 vaccines have changed the clinical scenario
of COVID-19. Multisystem inflammatory syndrome in children (MIS-C) has
been identified as an important cause of death of children with
COVID-19. Perturbations in immunity of T cells, B cells, and mast cells,
as well as autoantibodies and metabolic reprogramming may contribute to
the long-term symptoms of COVID-19. Atopic diseases, such as allergic
asthma and rhinitis, have been shown to be associated with a lower
susceptibility and better outcomes of COVID-19. At the beginning of
pandemic, EAACI developed guidelines that provided timely information
for the management of allergic diseases and preventive measures to
reduce transmission in the allergic clinics. The global distribution of
COVID-19 vaccines and emerging SARS-CoV-2 variants with reduced
pathogenic potential dramatically decreased the morbidity, severity, and
mortality of COVID-19. Nevertheless, breakthrough infection remains a
challenge for disease control. Hypersensitivity reactions (HSR) to
COVID-19 vaccines are low compared to other vaccines, and these were
addressed in EAACI statements that provided indications for the
management of allergic reactions, including anaphylaxis to COVID-19
vaccines. We have gained a depth knowledge and experience in the over 2
years since the start of the pandemic, and yet a full eradication of
SARS-CoV-2 is not on the horizon. Novel strategies are warranted to
prevent severe disease in high-risk groups, the development of MIS-C and
long COVID.
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