Neutralizing antibodies are highly predictive of immune protection against SARS-CoV-2 infection. A study analyzed data from seven vaccines and convalescent cohorts to estimate the neutralization level required for 50% protection against detectable infection, finding it to be 20.2% of the mean convalescent level (95% CI = 14.4–28.4%). For severe infection, the required level was significantly lower, at 3% of the mean convalescent level (95% CI = 0.7–13%). Modeling predicts that neutralization titers will decline over time, but protection from severe disease is likely to remain. Neutralization titers against some variants are reduced, and the model predicts the relationship between neutralization and efficacy against variants. The study shows that neutralization levels are a strong predictor of immune protection and provides a model for future vaccine strategies. The study also found that neutralization titers are predictive of protection from severe infection, with a 50% protective level of 3.0% of the mean convalescent level (95% CI = 0.71–13%). Protection from severe infection is expected to be more durable than protection from mild infection. The study suggests that neutralization titers may wane over time, but protection from severe disease may last longer. The model predicts that even without immune boosting, a significant proportion of individuals may maintain long-term protection from severe infection, though they may become susceptible to mild infection. The study highlights the importance of standardized assays for measuring SARS-CoV-2 immunity and the need for further research to refine immune correlates of protection. It also emphasizes the role of neutralizing antibodies in protection and the potential for other immune responses, such as T cell responses, to play a role in long-term protection. The study provides a framework for predicting future SARS-CoV-2 immunity based on available data and suggests that neutralizing antibodies will be an important predictor of vaccine efficacy in the future.Neutralizing antibodies are highly predictive of immune protection against SARS-CoV-2 infection. A study analyzed data from seven vaccines and convalescent cohorts to estimate the neutralization level required for 50% protection against detectable infection, finding it to be 20.2% of the mean convalescent level (95% CI = 14.4–28.4%). For severe infection, the required level was significantly lower, at 3% of the mean convalescent level (95% CI = 0.7–13%). Modeling predicts that neutralization titers will decline over time, but protection from severe disease is likely to remain. Neutralization titers against some variants are reduced, and the model predicts the relationship between neutralization and efficacy against variants. The study shows that neutralization levels are a strong predictor of immune protection and provides a model for future vaccine strategies. The study also found that neutralization titers are predictive of protection from severe infection, with a 50% protective level of 3.0% of the mean convalescent level (95% CI = 0.71–13%). Protection from severe infection is expected to be more durable than protection from mild infection. The study suggests that neutralization titers may wane over time, but protection from severe disease may last longer. The model predicts that even without immune boosting, a significant proportion of individuals may maintain long-term protection from severe infection, though they may become susceptible to mild infection. The study highlights the importance of standardized assays for measuring SARS-CoV-2 immunity and the need for further research to refine immune correlates of protection. It also emphasizes the role of neutralizing antibodies in protection and the potential for other immune responses, such as T cell responses, to play a role in long-term protection. The study provides a framework for predicting future SARS-CoV-2 immunity based on available data and suggests that neutralizing antibodies will be an important predictor of vaccine efficacy in the future.