CHMP5 and infection: Ideally, a vigorous antibody response in any infection correlates with good outcome but till-date no antibody threshold has emerged to correlate the protection against COVID-19 breakthrough infections.20 Neutralizing antibodies against the spike protein and its receptor-binding domain have been reported as primary immune predictors of protection against symptomatic infection and increasing antibody levels correlate with higher vaccine efficacy.21,22 In Pakistan, neutralizing antibody titers are not available, and only anti-S or anti-NPIgG antibody titers are available commercially.