Though COVID-19 cases are still declining globally, they are rising again in Africa and the Americas, the World Health Organization (WHO) said in its weekly pandemic report.

Meanwhile, in a closely watched vaccine development in the United States, Moderna today submitted its application for emergency use of its COVID-19 vaccine in children ages 6 months to 6 years old.

BA.4 and BA.5 fuel South Africa's rise

Globally, COVID-19 cases have been declining since the middle of March, and last week, cases fell 21% compared to the week before, while deaths declined 20% during the time period, the WHO said yesterday. It again urged caution in interpreting the trends, due to decreased levels of testing and sequencing.

However, it added that cases are up 32% in Africa and 9% in the Americas. At a WHO African regional office briefing today, officials said a spike in South Africa's activity is driving Africa's rise.

In a new preprint study, South African researchers detailed what they know about the Omicron BA.4 and BA.5 lineages that are contributing to the country's rising cases. Commenting on the study on Twitter, Tulio de Oliveira, PhD, one of the authors, said the lineages originated in the middle of December and early January, respectively. And though South African researchers characterized them, it's not clear where they originated. He directs South Africa's Centre for Epidemic Response and Innovation.

He said so far, a rapid increase in infections over the last 2 weeks hadn't led to large numbers of hospitalizations and deaths, though there is an early signal of rising hospitalizations in some of South Africa's provinces. The viruses have a growth advantage over BA.2 that is similar to what BA.2 had over BA.1, and scientists are currently working to characterize immune escape with the two viruses.

de Oliveira said coming 4 months after the Omicron BA.1 wave, waning immunity might be a contributing factor, but he said BA.4 and BA.5 impacts might play out differently by location, depending on the immunity situation.

In the Americas, cases were up 21% last week in the United States, most sharply in Puerto Rico, but increases were also high in parts of the Caribbean and in Argentina.

Though deaths were lower last week, South East Asia's and Africa's levels were higher, due to delays in reporting.

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