This person is confusing a decline in immune antibody titer.
Many people cofuse a decline in antibodies due to antigen decline with a decline in immunity,and mistake the phenomenon in which antibody titers peak after vaccination with an mRNA vaccine and then gecline in immunity.
Even if the number of lymphocytes in the blood decreases,they simply gather in lymph nodes,aphenomenon that can be seen with infections and other vaccinations.
