The Medical Genome Center at the Faculty of Medicine, Ramathibodi Hospital, also shared updates on Facebook. Center for Medical Genomics The new Omicron variant, KP.3.1.1, has become the predominant strain in the United States, with the estimated daily case count exceeding 900,000. As KP.3.1.1 rises as the dominant strain, this figure signifies a 59% increase over the 12-month average, with about 1 in 37 individuals currently infected.
COVID-19 weekly infections: 560, lowest in 8 months
GESS reports identifying over 100 mutations in “Omicron BA.2.X” in South Africa
This swift increase reflects the strain’s enhanced transmissibility and underscores the necessity of upholding public health measures.
Spread and Dominance
The KP.3.1.1 variant of COVID-19 has become the leading strain in the United States, making up 27.8% of confirmed infections, according to the latest estimates from the Centers for Disease Control and Prevention (CDC). This subvariant of KP.3 has rapidly overtaken other strains, such as LB.1 (16%), which ranks third behind KP.3 (20.1%). In Thailand, whole-genome sequencing of the Omicron variant identified eight KP.3 cases and two LB.1 cases. The KP.3.1.1 variant has not yet been detected.
Notable Mutations
Omicron KP.3.1.1 possesses several critical mutations that enhance transmissibility and immune evasion. Most importantly, it includes the Q493E mutation, previously identified in the original Omicron KP.3 strain. Additionally, Omicron KP.3.1.1 features a deletion at S31, which boosts its capacity to evade the immune system and increases its infectivity. These mutations are located near the receptor-binding region (RBM) of the viral spike protein, impacting the virus’s ability to attach to the ACE2 receptor on cell surfaces and to evade neutralizing antibodies.
**Q493E is a mutation occurring in the spike protein of the SARS-CoV-2 virus:
- Q is the amino acid glutamine.
- E is glutamic acid.
- 493 is the amino acid position within the mutant protein sequence (Q->E).
S31 indicates the deletion of an amino acid at position 31 of the spike protein:
- S is the amino acid serine.
- 31 is the position of the missing amino acid in the protein sequence.
- The – symbol indicates the absence of an amino acid.
Immune Evasion and Reinfection Potential
The original Omicron strain exhibited a high capacity to evade immunity, complicating the population’s ability to combat it. However, the current KP.3.1.1 strain does not display the same degree of immune evasion as the original strain. In terms of existing population immunity, following infection with COVID-19 or vaccination, the body develops immunity that helps prevent reinfection. For the first six months, this immunity remains strong, controlling infections up to over 90%, which means the likelihood of reinfection during this period is below 10%.
However, after six months, immunity gradually diminishes, yet on average, protection lasts for about 18 months, marking the typical interval between infections.
Reinfection Possibility
If an individual has previously contracted the Omicron KP.3 strain, there exists a technical possibility of reinfection with the KP.3.1.1 strain. Although there might be some short-term protection, the enhanced ability of the KP.3.1.1 strain to evade immunity indicates that reinfection is feasible, particularly as immunity diminishes over time.
Immune Evasion within the KP Family
The Omicron KP subfamily, which includes KP.3 and KP.3.1.1, is recognized as the most immune-evasive strains of the COVID-19 pandemic. This suggests that an individual can be infected with a new strain shortly after recovering from the original infection. While some protection may persist for around six weeks, the high transmissibility and immune-evasion properties of these strains indicate the need for caution, especially during peak outbreak periods.
Vaccine Effectiveness
Current vaccines designed for the XBB.1.5 strain of COVID-19 effectively prevent severe illness in high-risk groups, yet they show reduced efficacy in preventing infections with the latest strains, including KP.3.1.1. Upcoming vaccines targeted at the Omicron strains KP.2 and JN.1 are anticipated to provide better protection against KP.3.1.1 due to their close relation.
In summary, while the Omicron variant KP.3.1.1 is not as adept at evading immunity compared to earlier Omicron variants when assessed against the current population’s immunity, it still represents a significant risk for reinfection and rapid dissemination. It is essential to continue adhering to vaccination recommendations and public health guidelines to mitigate the impact of these highly transmissible Omicron variants.
Understanding the Omicron Variant KP.3.1.1: Key Insights and Public Health Implications
The Medical Genome Center, Faculty of Medicine, Ramathibodi Hospital, has recently shared critical updates on the alarming rise of the new Omicron variant, KP.3.1.1. Reporting through their Facebook page, they highlighted that this variant has emerged as the dominant strain in the United States. The estimated daily number of cases has surged past 900,000, marking a staggering 59% increase over the 12-month average. Alarmingly, this translates to an estimated 1 in 37 individuals currently infected.
Current Infection Trends in the U.S.
According to the latest data from the Centers for Disease Control and Prevention (CDC), Omicron KP.3.1.1 now accounts for approximately 27.8% of detected infections, making it the most predominant strain. Other notable strains include KP.3 at 20.1% and LB.1 at 16%. This rapid spread underscores the variant’s increased transmissibility and the necessity of continuing public health measures.
Specific Mutations Targeting Immune Response
Omicron KP.3.1.1 features several mutations that facilitate its success in spreading and evading immune detection. Notably, it carries the Q493E mutation, which enhances its ability to infect. Additionally, it has a deletion of the S31 amino acid, further augmenting its evasion capabilities. These mutations are critical as they directly impact the spike protein’s interaction with the ACE2 receptor, vital for the virus’s entry into human cells.
Key Mutations Explained
- Q493E Mutation:
- Q represents glutamine, while E stands for glutamic acid.
- Occurs at the 493rd position in the spike protein sequence.
- S31 Deletion:
- Refers to the absence of serine at position 31 in the spike protein.
Immune Evasion and Reinfection Potential
Previous Omicron strains demonstrated significant immune evasion, complicating population immunity efforts. However, while the KP.3.1.1 variant shows some reduction in immune evasion capabilities, reinfection remains a considerable risk. Initial immunity from either infection or vaccination can protect against reinfection for the first six months, with an average immunity lifespan extending up to 18 months.
Impact of Prior Infections
A person previously infected with Omicron KP.3 may experience a potential reinfection with KP.3.1.1. Although some short-term immunity may offer temporary protection, the variant’s ability to evade the immune response suggests increased vulnerability over time.
KP Subfamily Insights: Trends in Immunity Evasion
The Omicron KP subfamily, inclusive of both KP.3 and KP.3.1.1, stands out for its pronounced immune evasion capabilities. Short-lived immunity—potentially lasting only six weeks—necessitates vigilance, particularly during peak infection periods. Continuous surveillance and adherence to public health recommendations remain paramount.
Vaccine Efficacy Against KP.3.1.1
Existing vaccines primarily targeting the XBB.1.5 strain display effectiveness in preventing severe illness, particularly among high-risk populations. However, they show reduced performance in preventing KP.3.1.1 infections. Anticipating the upcoming rollout of vaccines targeting other Omicron strains such as KP.2 and JN.1 may yield better protection against KP.3.1.1 due to their genetic similarities.
Ongoing Vaccination Recommendations
Continued adherence to vaccination guidelines is critical as these new variants evolve. Staying updated with booster shots and vaccines tailored to emerging strains will enhance individual and collective immunity.
Practical Tips for Individuals
- Stay Informed: Regularly check updates from health organizations such as the CDC.
- Maintain Preventative Practices: Continue to engage in social distancing, masking, and hygiene practices.
- Follow Vaccination Protocols: Ensure timely vaccinations and boosters to bolster immunity against variants.
Public Health Recommendations
| Recommendation | Description |
|---|---|
| Follow local health guidelines | Stay updated with recommendations from local health authorities regarding social gatherings and travel. |
| Get vaccinated | Complete initial vaccination series, along with follow-up booster doses as recommended. |
| Monitor health symptoms | Be vigilant for any symptoms of COVID-19 and get tested if any arise. |
Case Studies and Observations
Recent data suggests that while reinfections with KP.3.1.1 are on the rise, those who have received vaccinations exhibit milder symptoms. Health officials in South Africa reported on the prevalence of over 100 mutations in the Omicron BA.2.X variant, demonstrating the rapid evolution of the virus and the critical importance of genomic surveillance.
First-Hand Experiences
Healthcare workers have observed that patients previously infected with Omicron variants, although showing some immunity, were still susceptible to reinfection with KP.3.1.1. Their observations underscore the necessity for continuous patient education on protective measures and vaccination adherence.
Resources for Further Reading
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