Understanding the Distinct Nature of Monkeypox and COVID-19
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Chapter 1: Introduction to Monkeypox
Have you ever considered why the 2022 monkeypox outbreak stands apart from COVID-19? This article delves into the differences between these two infectious diseases.
Before the year 2022, monkeypox was confined to certain regions in South Africa. However, by mid-September 2022, cases of monkeypox had surged to over 60,000 globally, affecting more than 100 countries. In light of this rapid increase, the World Health Organization (WHO) designated monkeypox a Public Health Emergency of International Concern (PHEIC) in July 2022, categorizing it alongside COVID-19, Ebola, and other significant infectious threats.
While both COVID-19 and monkeypox are classified as PHEIC, they differ significantly in their viral characteristics, modes of transmission, clinical manifestations, and treatment approaches. Familiarity with COVID-19 can serve as a valuable reference point for understanding monkeypox, enhancing our ability to make informed decisions.
Note: The monkeypox data referenced in this article is sourced from MonkeypoxTracker.net, which consolidates information from reputable organizations like the WHO, CDC, and Our World in Data. This user-friendly platform is updated daily, featuring various charts and graphics, along with real-time updates on Twitter.
Section 1.1: Virology of COVID-19 and Monkeypox
Both diseases are caused by distinct viruses: severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) for COVID-19 and monkeypox virus (MPXV) for monkeypox. SARS-CoV-2 is an RNA virus from the coronavirus family, while MPXV is a DNA virus belonging to the poxvirus family. Structurally, SARS-CoV-2 appears spherical with surface spikes, whereas MPXV has a brick-like shape with a smooth exterior. Notably, SARS-CoV-2 is considerably smaller than MPXV, measuring 100 nm compared to MPXV's size range of 220–450 nm.
SARS-CoV-2 emerged in humans in 2019, likely due to a spillover from bats or another intermediary host. In contrast, monkeypox was first identified in monkeys in 1958 and infected humans in 1970, probably through contact with small forest animals.
As these viruses circulate and adapt within human populations, various strains and variants have emerged. The predominant variant of SARS-CoV-2 is now Omicron, having previously included Alpha, Beta, Gamma, and Delta variants. Conversely, MPXV evolves at a slower rate, resulting in only two main clades: I (Central African) and II (Western African), with II further divided into IIa and IIb subclades. The IIb clade currently drives the global outbreak.
Subsection 1.1.1: Transmission Patterns
The video titled "What viruses are going around right now? COVID-19, mpox, human parvovirus and Oropouche virus" provides an overview of the current viral landscape, including COVID-19 and monkeypox.
In terms of transmission, SARS-CoV-2 is among the most contagious viruses, with an estimated basic reproduction number (R-naught) of 8.2 for the Omicron variant. This means that one infected individual can spread the virus to an average of eight others, leading to exponential growth if left unchecked. By mid-September, global COVID-19 cases exceeded 600 million.
On the other hand, monkeypox has a historically lower R-naught of 0.08, currently estimated between 1.4 and 1.8 during the ongoing outbreak. While a basic reproduction number greater than 1 indicates ongoing transmission, the lower figures for monkeypox suggest a less aggressive spread.
COVID-19 spreads primarily through respiratory droplets, whereas MPXV is primarily a skin infection requiring prolonged contact with infected lesions. Although monkeypox can also be transmitted through respiratory droplets, this is less common than skin-to-skin contact. Recent findings indicate that MPXV could aerosolize in certain situations, necessitating additional caution.
While anyone can contract SARS-CoV-2 due to its respiratory nature, monkeypox primarily affects those engaging in close, intimate contact, with over 98% of current cases reported among men who have sex with men. Nevertheless, monkeypox can still spread through indirect contact with contaminated objects, although experts consider this unlikely to pose a significant risk.
Section 1.2: Diagnostic Approaches
Both COVID-19 and monkeypox diagnoses rely on polymerase chain reaction (PCR) tests that detect specific genetic sequences unique to the respective viruses. COVID-19 testing requires nasopharyngeal samples, while monkeypox diagnosis necessitates samples from skin lesions. Rapid antigen tests are available for COVID-19, but they are unsuitable for monkeypox due to potential cross-reactivity with other orthopoxviruses.
Chapter 2: Clinical Courses of COVID-19 and Monkeypox
The incubation period—the time between infection and the onset of symptoms—varies between the two viruses: 3–5 days for SARS-CoV-2 (Omicron) and 7–21 days for MPXV.
The initial symptoms of COVID-19 may include fever, cough, sore throat, fatigue, headache, muscle pain, and loss of smell. As the illness progresses, shortness of breath may develop, and chest imaging can reveal lung damage. Severe cases may lead to respiratory failure, septic shock, and multi-organ failure.
In contrast, monkeypox typically presents with fever, swollen lymph nodes, and fatigue, followed by skin rashes that may evolve into blister-like lesions or scabs. Severe cases can lead to intense pain and structural deformities, with hospitalization often sought for pain management. Serious complications may include pneumonia, encephalitis, or sepsis.
Currently, the fatality rates for COVID-19 and monkeypox are ≤1% and 1–10%, respectively. However, measuring fatality rates can be complex due to variations in testing frequency, case definitions, and demographic factors.
The video "Walensky on how monkeypox differs from COVID-19" offers insights into the distinctions between these two diseases, enhancing our understanding of their clinical implications.
The COVID-19 fatality rate has decreased significantly due to widespread vaccination efforts. Similarly, the fatality rate for monkeypox during the current outbreak is much lower than historical data suggests. Outside of Africa, few monkeypox-related deaths have occurred, primarily in Brazil, where two deaths were reported among 5,726 cases by mid-September 2022, resulting in a fatality rate of 0.03%.
This lower fatality rate is attributed to the demographic characteristics of current monkeypox cases, predominantly affecting men who have sex with men, who typically face lower risks of severe disease. Vulnerable groups—such as children, pregnant women, and immunocompromised individuals—remain at greater risk.
Effective control of monkeypox is essential to prevent it from spreading to at-risk populations, which could lead to increased fatality rates. In the U.S., where monkeypox has been most prevalent, the percentage of positive tests appears to be declining, suggesting a potential subsiding of the outbreak due to vaccination and public health education.
Chapter 3: Treatment Options for Monkeypox and COVID-19
Fortunately, both COVID-19 and monkeypox have available treatments and vaccines. At the pandemic's onset, no treatments or vaccines existed for COVID-19, complicating management. Today, various medications—including immunomodulators and antivirals—are effective against COVID-19, in addition to several approved vaccines.
Unlike COVID-19, monkeypox is closely related to smallpox, which has been eradicated through mass vaccination efforts. Existing smallpox treatments and vaccines are thus applicable to monkeypox. Antivirals such as Brincidofovir and Tecovirimat are effective for monkeypox, and the replication-deficient vaccine Imvanex/Jynneos is approved for use. A replication-competent vaccine, ACAM2000, is also available but is less desirable due to potential side effects in immunocompromised individuals.
Conclusion: Key Takeaways on Virology, Transmission, and Treatment
In summary, COVID-19 and monkeypox are fundamentally different infectious diseases. Understanding their distinctions is vital, as both pose potential health risks. This article aims to enhance your knowledge of monkeypox through the lens of COVID-19, particularly regarding virology, transmission, clinical manifestations, and treatment options.
Author's note: this article is sponsored by monkeypoxtracker.net.