Kramer writes in his pre-print that you’ve linked:
>Of note, our observations are in contrast to a recent report by Long et al. that found waning titers 8 weeks post
138 virus infection as compared to acute responses (19). Especially in asymptomatic cases, antibody
139 responses disappeared after 8 weeks in 40% of individuals in the Long et al. study. However, the
140 antibodies measured in their paper were targeting the NP plus a single linear spike epitope. Much
141 more in agreement with our data, the same paper also reports relatively stable (slightly declining)
142 neutralizing antibody titers. The stability of the antibody response over time might therefore also
143 depend on the target antigen. The titers we measure here do correlate with neutralization as
144 discussed above.