When the body gets infected, it activates an immune defense that fights off the infection and provides protection against similar infections in the future. Vaccines can also train the body to recognize infectious agents, such as viruses, and fight them off in the future. This is the case also for the coronavirus (SARS-CoV-2), where previous infections and vaccines help the body fend off future infections.
A new study by researchers in South Africa suggests that the BA.4 and BA.5 versions of the Omicron variant are able to evade the body’s defense system built from previous infections and vaccines. This makes the BA.4 and BA.5 sub-variants spread widely, and they show increased risk of repeated infections.