Elsevier established a free COVID-19 resource center in January 2020, offering English and Mandarin information on the virus. The center grants permission for free access to its research in PubMed Central and other repositories for research use. The article discusses herd immunity in the context of COVID-19. Herd immunity occurs when a sufficient proportion of a population is immune, reducing the spread of a pathogen. It is often considered in vaccination programs to protect those who cannot be vaccinated. The basic reproduction number (R0) determines the herd immunity threshold, calculated as 1 - 1/R0. For R0 = 4, the threshold is 0.75. However, real-world factors like population structure and immunity waning affect herd immunity effectiveness. For SARS-CoV-2, the herd immunity threshold is estimated at around 67% if R0 is 3. Achieving this threshold through natural infection would result in a large number of deaths, making vaccination a better option. The article also discusses the complexities of SARS-CoV-2 transmission, including superspreading events and variations in infectivity. It highlights the importance of understanding these factors for effective public health strategies. The study emphasizes the need for vaccination programs to prevent widespread infection and reduce mortality. The article concludes that herd immunity should not be the ultimate goal without a vaccine, and instead, policies should focus on protecting vulnerable groups.Elsevier established a free COVID-19 resource center in January 2020, offering English and Mandarin information on the virus. The center grants permission for free access to its research in PubMed Central and other repositories for research use. The article discusses herd immunity in the context of COVID-19. Herd immunity occurs when a sufficient proportion of a population is immune, reducing the spread of a pathogen. It is often considered in vaccination programs to protect those who cannot be vaccinated. The basic reproduction number (R0) determines the herd immunity threshold, calculated as 1 - 1/R0. For R0 = 4, the threshold is 0.75. However, real-world factors like population structure and immunity waning affect herd immunity effectiveness. For SARS-CoV-2, the herd immunity threshold is estimated at around 67% if R0 is 3. Achieving this threshold through natural infection would result in a large number of deaths, making vaccination a better option. The article also discusses the complexities of SARS-CoV-2 transmission, including superspreading events and variations in infectivity. It highlights the importance of understanding these factors for effective public health strategies. The study emphasizes the need for vaccination programs to prevent widespread infection and reduce mortality. The article concludes that herd immunity should not be the ultimate goal without a vaccine, and instead, policies should focus on protecting vulnerable groups.