In the last months, there has been a notable increase in COVID cases, both in the United States and in Europe. An interesting review has been published on this fact in JAMA.
The increase in cases is due to the appearance of the BA.2 and BA-2.12.1 subvariants (both derived from the Omicron variant), together with the limited duration of protection conferred by the vaccine or a previous infection and the lifting of protective measures such as the mandatory use of masks.
These new variants are much more contagious and usually cause mild respiratory symptoms (sore throat and pharyngitis). Gastrointestinal symptoms (diarrhoea, nausea, vomiting) sometimes appear along with other non-specific symptoms (muscle aches, headaches, nasal congestion and tiredness).
New variants of coronavirus in Europe
Two other new subvariants have recently been detected in Europe: BA.4 and BA.5. It should be noted that people who have had an Omicron infection are not well protected against any of the new subvariants.
People vaccinated with two doses of RNA vaccines have limited protection against symptomatic disease caused by Omicron or BA.2 subvariants, although protection decreases over time, even with the third dose (4-6 months). However, the protection provided by the vaccine against severe respiratory disease, including hospitalization and death, lasts much longer.
What protection measures are recommended?
Because protection against symptomatic coronavirus infection declines over time, the CDC recommends administration of a fourth dose of vaccine to people over 50 years of age who received the third dose at least 4 months earlier.
The fourth dose is also recommended for immunosuppressed people if 4 months have passed since they received the last dose of vaccine. The purpose of vaccination is to protect against serious disease and not to prevent infection. Keep in mind that new variants of the coronavirus will continue to appear.
Finally, regarding the use of masks, there are people who wonder if it is useful to use them in places where there are people who do not wear them. We must remember that FFP2 masks protect in all circumstances and we believe that they should continue to be used.