Covid-19 vaccine regimen."While there was an increase in those with detectable antibodies after the second shot, the number of transplant recipients in our second study whose antibody levels reached high enough levels to ward off infection was still well below than in people with healthy immune systems," said study lead author Brian Boyarsky from the Johns Hopkins University School of Medicine in the US."Based on our findings, we recommend that transplant recipients and other immunocompromised patients continue to practice strict COVID-19 safety precautions, even after vaccination," Boyarsky said.The researchers noted that people who receive solid organ transplants, such as hearts, lungs and kidneys, often must take drugs to suppress their.