Pfizer and partner BioNTech plan to ask U.S. and European regulators within weeks to authorize a booster dose of the companies’ Covid-19 vaccine, based on evidence of greater risk of infection six months after inoculation and the spread of the highly contagious Delta variant.

The World Health Organization said on Friday that it was not clear whether Covid-19 booster vaccines will be needed to maintain protection, until further data is collected.

U.S. Covid-19 cases are up around 11 percent over the previous week – almost entirely among people who have not been vaccinated – officials said on July 8, as the highly infectious Delta variant becomes the dominant Covid-19 strain in the country.

The Olympics will take place without spectators in host city Tokyo, organizers said on July 8, as a resurgent coronavirus forced Japan to declare a state of emergency in the capital that will run throughout the Games.

Sanofi SA and GlaxoSmithKline Plc received an approval from Indian authorities for a late-stage clinical trial of their protein-based Covid-19 vaccine candidate, the drugmakers said on July 8.

The Delta variant is already the dominant strain of Covid-19 in the United States, according to data modeling done by the U.S. Centers for Disease Control and Prevention (CDC).

Britain said on July 7 the country would provide genomic sequencing support to Brazil, Ethiopia, Kenya, Nigeria and Pakistan to help identify, assess and track new variants of the novel coronavirus.

India’s Covid-19 deaths relative to infections hit a record high in June after cases peaked in early May, an analysis of government data shows, amid pressure on authorities to accurately report deaths from a second wave of the virus.

Israel reported on July 5 a decrease in the effectiveness of the Pfizer/BioNTech Covid-19 vaccine in preventing infections and symptomatic illness, but said it remained highly effective in preventing serious illness.

Johnson & Johnson said the company’s single-shot Covid-19 vaccine showed promise against the highly contagious Delta variant in a laboratory study.