Spontaneous reporting successfully highlighted thrombosis with thrombocytopenia syndrome (TTS) as a rare adverse reaction of Vaxzevria and Janssen vaccine. So, again it proved to be capable of detecting a rare adverse reaction. But it is unable to determine the incidence rate of the adverse reaction. Reporting rates are no incidence rates. Although it may give an indication reporting rates can’t be interpreted as an incidence rate. For an incidence rate, the nominator is inappropriate and the denominator suboptimal.