COVID-19 BA.4 and BA.5 variants account for more than HALF of US cases

New variants of COVID-19 are beginning to surge in the United States, with the much-dreaded BA.4 and BA.5 strains now accounting for about half of active cases in the country — according to the most recent sequencing data available.

The Centers for Disease Control and Prevention (CDC) revealed on Tuesday that the strains combine for 52% of cases sequenced in the week ending June 25 – combining to overtake the previously dominant BA 2.12.1 strain .

Both strains are believed to originate from South Africa, where the original Omicron strain was also first spotted. Unlike previous subvariants of the highly infectious strains, they are thought to be able to evade the natural immunity provided by previous Omicron infection.

This poses a big challenge for health officials, as many who should be safe from infection for months in the future can suddenly unexpectedly become reinfected and trigger a new outbreak.

However, the increase in these variants has not yet had much impact on the case numbers. Daily infections rose 10% to 109,384 per day, a range it has remained within for the past month. The United States is also recording 398 deaths per day, a 14% increase week-on-week.

Unlike previous strains of the virus, which moved mainly east to west in the United States, BA.4 and BA.5 are more prevalent along the west coast than the east coast.

The BA.5 variant now accounts for 36.6% of sequenced cases, according to the CDC, second only to BA 2.12.1 (42% of sequenced cases) as the most prevalent strain in the nation. BA.4, which shares many of the same traits as BA.5, accounts for 15.7% of cases.

Every case sequenced in the United States is a form of the Omicron variant, as the highly infectious strain that emerged in late 2021 snuffed out other versions of the virus.

The once-dominant “stealth” BA.2 variant now accounts for less than six percent of Covid cases in the United States. The original BA.1 Omicron strain is no longer detected.

The strains alarmed health officials after early data from South Africa showed that a person’s natural immunity against a previous infection is not as effective against it as other strains.

Although their rise has yet to impact national case figures, some experts are warning that more localized outbreaks are on the way.

In New York, Dr Jay Varma, former public health adviser to Mayor Bill de Blasio, warns BA.5 could be the reason case numbers in the nation’s largest city are no longer falling.

‘The fall in reports [COVID-19] cases in New York have ceased. Reported cases are at a high plateau, meaning actual transmission is very high when you factor in >20x undercount. This is probably the start of a BA.5 wave,” he said in a Tweeter.

According to CDC data, BA.5 accounts for nearly one in three cases in the New York and New Jersey area. BA.4 accounts for nearly 12% of cases, while BA 2.12.1 remains dominant.

Unlike the usual strains of Covid, which take root along the east coast before spreading west over time, these two strains first took hold on the other side of the country.

BA.5 accounts for 36% of cases sequenced along the West Coast and 38% in the Pacific Northwest. It is most prevalent in the Dust Bowl, where it accounts for 41% of sequenced cases, and the Southwest, where it is at 40%.

New strains that break the general rules of the pandemic – that once a person is infected, they can’t catch the virus again for a period of time – change the calculus of the viral response.

Fearing the new strains, the Food and Drug Administration (FDA) plans to roll out newly formulated COVID-19 vaccines that specifically target the Omicron variant.

By a vote of 19 to 2, the Vaccines and Related Biologicals Advisory Committee (VRBPAC) approved plans to roll out newly formulated vaccines this fall – citing Omicron variant vaccine resistance traits.

All currently available versions of COVID-19 vaccines are formulated for the original Wuhan strain that emerged two years ago.

While still effective in preventing severe infection or death in the majority of cases, the Omicron variant has mutated to avoid frontal protection against infection.

This change allows both Pfizer-BioNTech and Moderna to begin distribution of newly formulated vaccines that should be able to prevent infection with the Omicron variant – as well as previous versions of the virus.

The FDA is expected to follow the lead of its advisers and issue emergency use authorization to the new jabs at some point this week.

After the FDA, and the Centers for Disease Control and Prevention (CDC) will likely allow injections as well.

Dr. Peter Marks, director of the Center for Biologics Evaluation and Research, the FDA’s lead regulator for vaccines, said Tuesday morning that he hopes to make the new vaccines available as early as October.