Key Highlights:
- Clade I vs. Clade II: The current mpox strain outbreak involves a more transmissible and potentially more severe version of clade I, unlike the 2022 outbreak caused by clade II.
- Transmission Patterns: Clade I is spreading not only through sexual contact but also potentially through animal exposure and household transmission, with cases emerging outside Africa.
- Severity and Symptoms: The new strain has a higher fatality rate in the Congo, but with vaccination and better healthcare, the threat may be lower in other regions.
The World Health Organization (WHO) has once again declared mpox a global public health emergency, raising concerns that this latest strain might be more severe than the one that spread in 2022. But how different is this new strain, and should we be more worried?
What Is the Difference Between the 2022 Mpox Strain and the Current One?
Mpox, previously known as monkeypox, is a viral infection that causes painful lesions and spreads through direct contact with an infected person, animal, or contaminated objects like clothing or bedding. The virus is categorized into two groups: clade I and clade II.
In 2022, the outbreak was caused by clade II, leading to around 100,000 cases worldwide. However, the current outbreak, which began in January 2023 in the Democratic Republic of Congo, involves a version of clade I, which has since spread to 12 other countries in the region.
Read this also: Kylie Jenner and Timothée Chalamet’s Private Moments in Public Goes Viral, See Pics
Sweden recently confirmed the first known infection of clade I outside Africa, while Pakistan also reported a case of mpox on Friday, though the strain has not yet been identified.
Clade I is more transmissible and potentially more severe than clade II, raising concerns about further international spread. “We should have learned a lesson from 2022 that an infection anywhere is potentially an infection everywhere,” said Anne Rimoin, an epidemiology professor at UCLA Fielding School of Public Health.
How Does This New Mpox Strain Spread?
Mpox has traditionally spread through close personal contact, contaminated materials, or contact with infected animals. During the 2022 outbreak, clade IIb was primarily transmitted through sexual contact, especially among men who have sex with men.
The current outbreak in the Democratic Republic of Congo shows a similar pattern, with clade Ib spreading through sexual contact among female sex workers and men who have sex with men. However, Dr. Stuart Isaacs, an associate professor of medicine at the University of Pennsylvania, noted that much of clade I’s spread could be due to exposure to animals and transmission within households.
Early evidence suggests that clade Ib may have certain properties that make it spread more easily from person to person.
Are the Recent Cases More Severe?
Historically, clade I outbreaks have been deadlier than those caused by clade II, with death rates as high as 10%. However, recent outbreaks have seen lower mortality rates. In the current Congo outbreak, around 22,000 cases have been reported, with more than 1,200 deaths, putting the fatality rate just above 5%.
By comparison, clade II outbreaks in Africa have had a mortality rate of around 1%, and the 2022 global outbreak saw only 0.2% of cases result in death. The severity of the disease can vary based on factors such as the route of transmission, the individual’s immune system, and the source of infection.
In the U.S., the threat could be milder due to better healthcare access and less malnutrition, according to Marc Siegel, an associate professor of medicine at the George Washington School of Medicine and Health Sciences. Vaccines for mpox are also widely available in the U.S., with two doses of the mpox vaccine or a previous clade II infection offering protection against severe illness from clade I.
Do Symptoms Differ Between the Clades?
Mpox symptoms generally start with a rash that progresses to blisters filled with whitish fluid and eventually scabs over. Other symptoms may include fever, headache, muscle aches, back pain, low energy, and swollen lymph nodes. Severe cases can lead to more widespread lesions, secondary bacterial infections, pneumonia, heart inflammation, or brain swelling. Immunocompromised individuals are at higher risk of hospitalization and death.
During the 2022 outbreak, lesions were often found around the genital and anal regions or inside the mouth and throat, likely due to how the virus was spreading at that time. Some cases in the current Congo outbreak have also shown similar patterns, though experts are still trying to understand the full extent of these changes.
Read this also: Suri Cruise’s Summer Style: How She Keeps It Cool in NYC
Amira Albert Roess, a professor of global health and epidemiology at George Mason University, noted that there are more reports of genital lesions in this outbreak compared to previous clade I outbreaks, but it will take time to fully understand the implications.
Conclusion
While the new mpox strain appears more transmissible and potentially more severe, much remains to be understood about its behavior and impact. Vigilance and preventive measures, including vaccination, remain crucial in controlling its spread and protecting public health.
