By making up 53.6% of cases as of July 8, the COVID-19 Omicron subvariant BA.5 is now the predominant strain spreading in the country.
In February 2022, the variation was discovered for the first time in South Africa, where it quickly increased the number of infections.
BA.5 may be the most contagious variety to date, and data from many pre-print studies (that have not yet undergone peer review) suggest that it may be able to partially bypass immunity from prior infections and vaccinations.
Additionally, data demonstrate that even while BA.5 is increasing the number of infections, prior infections and vaccine-induced immunity continue to shield the majority of patients from serious illness, in-patient stays, and even death.
According to Monica Gandhi, an infectious disease specialist with UCSF, “South Africa has excellent genomic surveillance and data output and has shown us that BA.5 is likely to cause rises in cases (as it already does in the U.S.), but not major increases in severe disease with the degree of population immunity we now have in this country.”
What to know about BA.5 in other countries
In South Africa, BA.5 spread quickly, dramatically increasing the number of cases, but not filling hospitals to capacity.
Bernadette Boden-Albala, the director and founding dean of the program in public health at the University of California, Irvine, claims that there was no increase in the number of fatalities in South Africa and that the BA.5 wave was not as intense as earlier surges.
In Portugal, where COVID immunization and enhanced rates are high, BA.5 led to an increase in hospitalizations.
However, this isn’t surprising, according to Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security and an expert in infectious diseases, given Portugal didn’t have any significant outbreaks of earlier Omicron subvariants.
According to Adalja, “In Portugal, hospitalization rates increased [with BA.5], but they had less severe earlier omicron variant waves, which in most cases would be protective against severe disease from newer variations. The United States will perform similarly to South Africa.
“I think the U.S. is likely to follow the South African path,” Adalja said. “Infections will rise but will be substantially decoupled from hospitals being overburdened as immunity from past Omicron variants coupled with Paxlovid and monoclonal antibodies will be operational.”
BA.5 is more contagious and immune-evasive
Recent unreviewed research indicates that BA.5 spreads faster than earlier versions. This is how, according to Boden-Albala, it swiftly surpassed the highly contagious BA.2 form to become dominant in many regions of the world.
According to Boden Albala, the number of BA.5 cases has climbed by 10% just in the last week.
Additional preliminary studies reveal that BA.5 also possesses immune-evasive characteristics, which reduces the effectiveness of the vaccine in defending individuals against symptomatic diseases.
BA.5 has alterations in its spike proteins that give it a greater ability to elude the body’s immune response to previous COVID infection, especially if immunity is fading, and protection from the vaccinations that were developed to attack the original COVID strain.
Our initial line of defense against infection, antibodies, appear to be outwitted by BA.5. According to Gandhi, our cellular immunity—our T cells and memory B cells—seems to be holding up well, shielding people from serious illness, hospitalization, and death.
Additionally, according to recent data from Qatar, natural infection, which may have occurred up to 14 months ago, is still 97 percent protective against severe disease when combined with the current subvariants, including BA.5. Additionally preliminary, this study has not yet undergone peer review.
Two dose vaccines continue to provide high rates of protection against severe disease with BA.5 and BA.4 variants (87 percent protection against hospitalization according to South Africa data), which is probably because T cell immunity from the vaccines continues to be protective across variants, from alpha to omicron, Gandhi said.
Unvaccinated patients continue to have the highest risk of dying in hospitals, as is the case with all versions, including BA.5.
According to Gandhi, the number of cases will increase in the United States as a result of the antibodies’ decreased capacity to prevent BA.5 infection, but the prevalence of severe illness will stay low.
Changing opinions regarding COVID-19
Meanwhile, a recent Pew Research Center survey found that Americans are less likely than before to believe that COVID-19 poses a hazard to the public’s health.
The proportion of Americans who consider COVID-19 to be a serious threat to the health of the American populace decreased from 57 percent to 41 percent between January 2022 and May 2022.
