evidence: In recent weeks, though, mixed messaging about the safety and efficacy of the vaccines — whether they work, whether they protect against the new coronavirus variants, whether we can ever stop masking and social distancing — has many experts concerned that even more people will opt out. [...] There is already evidence to support this, she says. First, when the vaccines were studied in macaque monkeys (during preclinical testing), they did eliminate asymptomatic infection — researchers swabbed the vaccinated macaques’ noses and found little or no virus. Second, the types of antibodies that are stimulated by most systemic vaccines (IgG and IgA) do tend to block viral infection in the nose (and no viral load in the nose most likely translates to no transmission). Finally, when monoclonal antibodies are given to COVID-19 patients, those antibodies reduce the viral load throughout the respiratory tract, including the nose. [...] For the last few months, concern has been growing that a number of SARS-CoV-2 variants — mutated versions of the virus that seem to be contributing to greater numbers of hospitalizations and deaths in some parts of the world — could render the vaccines impotent.