Long-Term Immunity and Antibody Response: Challenges for Developing Efficient COVID-19 Vaccines

Questions and concerns regarding the efficacy and immunogenicity of coronavirus disease 2019 (COVID-19) vaccines have plagued scientists since the BNT162b2 mRNA vaccine was introduced in late 2020. As a result, decisions about vaccine boosters based on breakthrough infection rates and the decline of antibody titers have commanded worldwide attention and research. COVID-19 patients have displayed continued severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-spike-protein-specific antibodies and neutralizing antibodies in longitudinal studies; in addition, cytokine activation has been detected at early steps following SARS-CoV-2 infection. Epitopes that are highly reactive and can mediate long-term antibody responses have been identified at the spike and ORF1ab proteins. The N-terminal domain of the S1 and S2 subunits is the location of important SARS-CoV-2 spike protein epitopes. High sequence identity between earlier and newer variants of SARS-CoV-2 and different degrees of sequence homology among endemic human coronaviruses have been observed. Understanding the extent and duration of protective immunity is consequential for determining the course of the COVID-19 pandemic. Further knowledge of memory responses to different variants of SARS-CoV-2 is needed to improve the design of the vaccine

Why Is Fertility Lower in Wealthier Countries? The Role of Relaxed Fertility-Selection

Lower fertility in wealthier countries can be explained in evolutionary terms by three key factors: (i) higher fertility in poorer countries-an evolutionary consequence of many generations of intense "fertility-selection" favoring innate behaviors promoting high fertility, especially in males; (ii) the empowerment of women in wealthier countries that serves to reduce fertility directly-an evolutionary consequence of selection favoring an inherent preference for lower fertility in females, combined with release from the evolutionary effects of a long history of male control over female fertility; and (iii) offspring access in wealthy countries to public health care, welfare, and other social services, which combined with inherited wealth for offspring, virtually eliminates competition between families for the resource needs of offspring. The combined consequences of (ii) and (iii) mean that the fertility-selection so prevalent in poor countries is relaxed in wealthy countries, thus allowing random genetic drift to produce an increased relative frequency of innate behaviors promoting low fertility and discontentment with high fertility. Copyright 2005 The Population Council, Inc..