The effectiveness of vaccinations against new variants would also dictate when, where, and how often additional shots are needed. According to Pfizer’s latest trial, the two-dose vaccine appears extremely successful for at least six months, and potentially longer. Additionally, six months after receiving the second requisite injection, those that received Moderna’s vaccine retained significant amounts of virus-fighting antibodies. Although the new COVID-19 vaccines are expected to last at least a year, they are unlikely to have lifetime immunity, like measles vaccinations do, according to Dr. Kathleen Neuzil, a vaccine specialist at the University of Maryland. Present vaccinations are targeted against a specific spike protein found in coronaviruses, according to Mehul Suthar of the Emory Vaccine Center. If the virus evolves sufficiently over time, vaccinations may need to be modified to maintain efficacy.The vaccinations tend to be protective against the prominent strains that have arisen, albeit somewhat less so against the one initially discovered in South Africa.

Reference

How long does protection from COVID-19 vaccines last?,https://www.woodtv.com/covid-19-vaccine/how-long-does-protection-from-covid-19-vaccines-last/