Updated Jan 23, 2021 | 14:13 IST Early reports indicated that such antibodies decline substantially over less than six months. This raised questions about how long protective immunity might last following an infection. COVID-19: Is natural immunity better than vaccine-acquired immunity? | Photo Credit: iStock Images New Delhi: During the early days of the COVID-19 pandemic, it was unclear whether and how individuals and populations would develop protective and lasting immunity against SARS-CoV-2, the novel coronavirus that causes COVID-19 disease. People lived in a limbo of whether they would gain immunity after infection or vaccination. Therefore, the initial focus was on understanding and defining virus neutralising antibodies from B cells after infection. Early reports indicated that such antibodies decline substantially over less than six months. This raised questions about how long protective immunity might last following an infection.