  Mobile phone data have played a key role in quantifying human mobility during
the COVID-19 pandemic. Existing studies on mobility patterns have primarily
focused on regional aggregates in high-income countries, obfuscating the
accentuated impact of the pandemic on the most vulnerable populations. By
combining geolocation data from mobile phones and population census for 6
middle-income countries across 3 continents between March and December 2020, we
uncovered common disparities in the behavioral response to the pandemic across
socioeconomic groups. When the pandemic hit, urban users living in low-wealth
neighborhoods were less likely to respond by self-isolating at home, relocating
to rural areas, or refraining from commuting to work. The gap in the behavioral
responses between socioeconomic groups persisted during the entire observation
period. Among low-wealth users, those who used to commute to work in
high-wealth neighborhoods pre-pandemic were particularly at risk, facing both
the reduction in activity in high-wealth neighborhood and being more likely to
be affected by public transport closures due to their longer commute. While
confinement policies were predominantly country-wide, these results suggest a
role for place-based policies informed by mobility data to target aid to the
most vulnerable.
