The researchers noted that a similar report, authored by Long et. al, produced results that found waning titers 8 weeks post viral infection. In asymptomatic cases, antibody responses disappeared after 8 weeks in 40% of individuals. However, the antibodies measured in the report were NP antibodies plus a single linear spike epitope. The report also shows relatively stable (slightly declining) neutralizing antibody titers, in agreement with the study assessing the longevity of spike antibodies. The stability of the antibody response over time might therefore also depend on the target antigen.