Weekly COVID-19 cases dropped to their lowest level since February, though many countries are still struggling with sparse vaccine supply, the spread of variants, and overburdened health systems, the World Health Organization (WHO) said yesterday in its weekly snapshot of the pandemic.In other developments, the WHO said it is tracking one more variant of concern, first seen in Peru and called Lambda, which has genetic markers suggesting that it is more transmissible.Complex picture with rises in some countriesIn its weekly epidemiological update, the WHO said global cases were down 12% last week compared with the previous week, with declines seen in all world regions except Africa.