United States: Health experts foresee an escalation in COVID-19 cases as the summer progresses, driven by the proliferation of another terrifying variant.
The KP.2 variant now constitutes 28% of COVID-19 cases in the United States, a significant increase from a mere 6% in mid-April, as per the latest data from the Centers for Disease Control and Prevention (CDC) released on Friday, according to reports by NBC News.
By late April, KP.2 had become the predominant strain, surpassing the JN.1 variant, which dominated during the winter months.
Researchers collectively refer to KP.2 and another variant, KP.1.1, which shares similar pivotal mutations, as “FLiRT” — an acronym highlighting their specific amino acid alterations.
Both variants descend from JN.1, itself part of the Omicron lineage, which has been the prevailing form of the coronavirus over the past several years.
However, KP.2 features three additional mutations in its spike protein compared to JN.1. These mutations potentially enhance the virus’s ability to evade immune defenses provided by vaccines or previous infections.
“These extra mutations appear to increase immune evasion; hence, it’s not unexpected that KP.2 would become dominant,” stated Dr Dan Barouch, head of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston.
Laboratory research from Japan, available as a preprint and yet to undergo peer review, indicates that the COVID-19 vaccines currently endorsed in the US may be less effective against KP.2 compared to JN.1, as per NBC News.
Nevertheless, the same research suggests that KP.2 may be less proficient at infecting cells, implying that a higher viral load might be required to cause infection.
Individuals previously infected with JN.1 are expected to retain some level of protection against KP.2, according to experts.
The CDC does not routinely collect data on the evolution of COVID-19 symptoms, making it challenging to determine if KP.2 results in different clinical manifestations. Generally, Covid-19 symptoms have remained consistent over the past few years.
Projected Modest Increase in Covid Cases This Summer
Covid-19 cases have historically surged every summer in the US since 2020. Should KP.2 continue its ascension, this pattern may persist, albeit less dramatically, experts suggest.
The US is currently well-positioned regarding Covid-19 as summer approaches, according to Andrew Pekosz, a virologist at Johns Hopkins University. Hospitalizations reached unprecedented lows at the end of April, the last dataset before the CDC ceased mandating hospital reporting of Covid admissions.
“We observe a late summer to early fall increase in cases, followed by another surge around the Christmas holidays and New Year,” Pekosz stated. “This pattern has repeated over the past few years, but importantly, the magnitude of cases has steadily decreased.”
Several factors might facilitate the spread of the KP.2 variant this summer. As temperatures rise, people tend to seek refuge indoors, creating environments conducive to viral transmission. Additionally, vaccination rates have lagged, with less than a quarter of US adults having received the updated COVID-19 vaccine, reports by NBC News mentioned.
“There will likely be a considerable susceptible population due to waning immunity and viral evolution, leading to a notable number of cases this summer,” said Dr. Thomas Russo, chief of infectious diseases at the University at Buffalo Jacobs School of Medicine and Biomedical Sciences. However, he noted that widespread existing immunity could mitigate the severity of this wave compared to previous years.
Dr. Barouch mentioned that past summer surges have coincided with the emergence of new variants, suggesting a similar scenario this year.
“Summer increases have often correlated with new variants, such as the Delta and BA.5 waves,” he said. “So, another summer surge wouldn’t be surprising.”
Implications of KP.2 for Vaccine Recommendations
The emergence of KP.2 poses significant considerations for public health officials deciding on the target variants for upcoming COVID-19 vaccines.
The Food and Drug Administration (FDA) recently postponed an advisory committee meeting intended to determine which strains to incorporate into the updated vaccine formula for the fall.
“We have observed recent shifts in the dominant circulating strains of SARS-CoV-2,” an FDA spokesperson commented. “The additional time will allow us to gather more current surveillance data and other relevant information to inform the committee’s discussions and recommendations.”
In its most recent vaccine guidance from February, the CDC recommended an additional dose for individuals aged 65 and older, with younger individuals considering one if needed.
Dr. Barouch advised that those who have not received the updated shot and feel it necessary should get the currently available vaccine.
Conversely, Pekosz suggested that those who are not immunocompromised could likely wait until the fall for the new formulation.
“Given the current low case numbers, it seems prudent to wait until September for the updated vaccine,” he remarked.