A boy gets tested for COVID-19 after vaccinated family members tested positive for the coronavirus, in North Miami, Florida on Aug 9, 2021. (MARTA LAVANDIER / AP)

WASHINGTON / PRAGUE / LOS ANGELES – The newer and most contagious Omicron subvariants, known as BA.4 and BA.5, now make up over 80 percent of COVID-19 infections in the United States, according to data released by the US Centers for Disease Control and Prevention on Tuesday.

The BA.5 subvariant accounted for 65 percent of new infections in the latest week ending July 9, while BA.4 accounted for 16.3 percent of new infections, CDC data show

The BA.5 subvariant accounted for 65 percent of new infections in the latest week ending July 9, while BA.4 accounted for 16.3 percent of new infections, CDC data show.

BA.5 has become the dominant variant in the United States.

Confirmed cases contracted by the two subvariants have kept increasing since mid-May, CDC data show.

The two subvariants are more contagious than earlier variants of Omicron, and also appear to evade protection from vaccines and previous infections more easily than most of their predecessors, according to health experts.

"Cases are already rising again in the United States, and could rise substantially later this summer or in the fall, when there is a return to offices, schools, and other indoor facilities," Jeffrey Sachs, professor and director of the Center for Sustainable Development at Columbia University, told Xinhua in a recent interview.

ALSO READ: WHO: COVID-19 pandemic 'nowhere near over'

Experts stressed that current public health tools, including masking indoors, avoiding crowds and getting booster shots, are still very effective against severe illness, hospitalizations and deaths caused by BA.4 and BA.5. 

A healthcare professional prepares a dose of COVID-19 vaccine for health and social care workers at the Life Science Centre at the International Centre for Life in Newcastle upon Tyne, northeast England, on Jan 9, 2021. (OWEN HUMPHREYS / POOL / AFP)

Alnylam Pharmaceuticals Inc escalated its patent fight with Pfizer Inc and Moderna Inc over their COVID-19 vaccines on Tuesday, accusing the companies in Delaware federal court of infringing a newly obtained patent.

The lawsuits said the vaccines' messenger-RNA delivery systems violate an Alnylam patent on lipid nanoparticle technology for delivering genetic material into human cells. The US Patent and Trademark Office issued the patent the same day Alnylam filed the complaints.

Cambridge, Massachusetts-based Alnylam first sued Pfizer and Moderna in March for allegedly infringing an LNP patent

Pfizer, its German vaccine partner and co-defendant BioNTech SE, and Moderna did not immediately respond to requests for comment. Alnylam and its attorneys also did not respond to requests for comment.

ALSO READ: Moderna to advance two Omicron vaccine candidates

Several biotech companies have filed patent lawsuits this year over the LNP technology in Pfizer and Moderna's COVID-19 vaccines.

Cambridge, Massachusetts-based Alnylam first sued Pfizer and Moderna in March for allegedly infringing an LNP patent. Alnylam has said in all of the lawsuits that its technology is "essential" to the vaccines.

Pfizer denied those allegations in May and responded that Alnylam knows the vaccine is "outside the scope of what Alnylam actually invented." Moderna told the court it was immune from Alnylam's claims because it provided the shots for the US government's national vaccination program.

ALSO READ: Hit by COVID-19, EU population shrinks for second year running

Alnylam's Tuesday lawsuits accused New York-based Pfizer and Cambridge, Massachusetts-based Moderna of infringing a patent covering a specific class of LNPs and a method for manufacturing them.

The new lawsuits, like Alnylam's other lawsuits, ask for an unspecified share from vaccine sales. Pfizer has said that it expects $32 billion in revenue from its vaccine this year, while Moderna forecast $21 billion from its shots.

A woman wearing a face mask walks to get tested for COVID-19 at a sampling station in Prague, Czech Republic, Sept 18, 2020. (PETR DAVID JOSEK / AP)

Czech Republic

The number of daily COVID-19 cases in the Czech Republic exceeded 2,000 for the first time since late April, data from the country's Health Ministry showed Tuesday.

The country recorded 2,031 new cases on Monday, a one-third increase week-on-week. The daily number of COVID-19 hospitalizations also continued to rise, reaching 305 on Monday compared to 286 a week ago.

The number of daily infections in the country started to rise at the end of June. More than 1,000 daily cases were recorded for five consecutive working days in the last week of June.