2024-08-28 14:15:40
On August 14, 2024, the Director-General of the World Health Organization (WHO) stated “Public health emergency of international concern” Regarding the monkeypox (formerly known as “monkeypox”) outbreak in the Democratic Republic of the Congo (DRC).
What is France’s vaccination strategy? What is the status of vaccine supply in Africa? Why is the situation worrisome when there are effective vaccines and reliable diagnostic tests? Let’s take stock.
Why did the World Health Organization issue a global health alert about MPOX?
The current MPOX outbreak in the Democratic Republic of the Congo did not start in August 2024… but in November 2023. The first case of MPOX was discovered in humans in 1970the Democratic Republic of the Congo has experienced several MPOX outbreaks. If the Director-General of the World Health Organization declares that this new epidemic constitutes a “public health emergency of international concern,” it is caused by several major events.
First, a research team from the National Institute of Biomedical Research (INRB) was on site in the Democratic Republic of Congo A new branch of the virus identified ;Clade is the appropriate scientific term for two “variants” of the same virus that are distinguished by genomic mutations (i.e., genetic inheritance).
This new clade was named clade 1b to distinguish it from another clade, 1a, which was The only one previously circulated in the Democratic Republic of the Congo.
The World Health Organization is concerned about the rapid spread of this new clade 1b in the Democratic Republic of the Congo and neighboring countries.
At the current level of knowledge, what do we know about the peculiarities of new clade 1b?
It should be remembered that mpox usually behaves as skin rash, sometimes very severe Pustules develop and then scabs form. Type 1a mainly affects children under 15 years of age and is transmitted through close skin-to-skin contact with these lesions.
On the other hand, the newly discovered clade 1b has effects on adults and transmitted in a privileged manner during sexual encounters. This contamination of new clade 1b through sexual contact has attracted the attention of the World Health Organization.
A woman contaminated with MPOX developed lesions on her arms.
Chandru Nitanga/AFP
Another difference: in children contaminated with clade 1a, lesions may appear throughout the body, sometimes on mucous membranes (which can interfere with eating), in the eyes, etc. More concentrated on the genitals.
However, it is important to emphasize that a new clade 1b is emerging, so scientists still lack the perspective to describe it.
Therefore, many questions remain to be clarified in terms of transmission: Is this new branch more transmissible than the branch that spreads in 2022? In addition to contamination through genital injury and close physical contact, can new branch 1b also be transmitted through liquids such as breast milk, semen, vaginal secretions, etc.?
Finally, concerns have been raised about the lethality (i.e., the percentage of people infected with MPOX who die) of this new clade 1b.
Mpox virus particles (pink) in infected cells (green) cultured in the laboratory, stained and viewed under a transmission electron microscope.
NIAID, copy
Since early 2024, the World Health Organization has reported high case fatality rates about 4% All suspected cases of contamination with MPOX clade 1a and 1b viruses in the Democratic Republic of the Congo. This means nearly 4 out of every 100 people infected will die. But the numbers are higher for infants and young children.
What is the difference between the current epidemic and the epidemic in 2022?
Currently, in Democratic Republic of the Congo and surrounding countriesprevalent in clade 1a (mainly transmitted through skin lesions, present in the Congo Basin for decades) and clade 1b (newly discovered, transmitted through sexual contact).
There is another branch of mpox called branch 2. It was this clade 2, more precisely clade 2b (genetically modified from the original clade 2) that caused the 2022 outbreak in Europe, the Americas and Asia.
During this global outbreak, clade 2b transmission through sexual contact was observed, particularly among men who have sex with men. At the time, this was the first time that the MPOX virus could be transmitted through sexual intercourse.
Why do clades have different inheritance patterns?
Evolution of viruses since their description First appeared in humans in 1970let us understand how this virus spreads and the profile of those infected. Initially, mpox was transmitted from animals to humans and often affected children after contact with animals.
In this regard, it is worth noting that although the name “monkey pox” (meaning “monkey pox” in English) has long been used, the animals involved are generally rodents, not monkeys.
Is there a vaccine for this new pox epidemic?
Health authorities recommend vaccination France According to the latest instructions issued by the Superior Health Authority during the branch 2 multi-country epidemic, taking into account its good tolerability and effectiveness (estimated between 76% and 87% after the first dose), as internationally (Notice of July 8, 2022 updated on January 3, 2023). This is the so-called “third generation” smallpox vaccine (MVA-BN vaccine) Modified Ankara vaccinedeveloped by Bavarian Nordic of Denmark).
Since mpox and smallpox belong to the same family orthopoxviruswhich allows vaccines developed against smallpox viruses to be used against MPOX.
Notice The World Health Organization also recommends the use of two other vaccines (Another third-generation smallpox vaccine developed in Japan may even allow a second-generation vaccine to be used if a third-generation vaccine is not available).
The third-generation vaccines recommended in France are sold under the brand names Imvanex or Jynneos. exist son website internetdesignated by the French Ministry of Health vaccination strategy In particular, the recommended number of doses (one or two doses) depends on whether childhood smallpox vaccine was received before 1980. Case information.
Two years ago, during the 2b branch epidemic in France, high-risk groups and people who had been in contact with patients were vaccinated. But as far as the current epidemic is concerned, there are still some problems in the vaccination strategy: Do people who have been vaccinated need to be vaccinated again in 2022? Two years later, are they still protected from clade 2b? Finally, scientists want to know whether the vaccine will be equally effective against the clade we just identified.
Why is the global situation still worrying despite a vaccine?
To combat MPOX, there is a vaccine that has shown its effectiveness in previous outbreaks and Reliable biodiagnostic tools (Test based on PCR technology, used in “polymerase chain reaction” or “polymerase chain reaction”Editor’s Note). These methods are available in countries such as France.
Regarding vaccines, the key issue is the lack of access to vaccines in the Democratic Republic of the Congo. The country is experiencing recurring epidemics of acne, and so far, there is no vaccine to protect its population.
Also worth mentioning is the apparent lack of availability of biodiagnostic tests. The complexity of this outbreak also stems from the fact that biological diagnostics are not universally available and scarce in the Democratic Republic of the Congo, especially in remote areas.
When we are faced with clinical findings suggestive of chickenpox (what we call a differential diagnosis), we also think of diseases such as chickenpox or measles, especially in children. We then learned how difficult case counting and surveillance is for health workers and caregivers, who need to make diagnoses based on lesions that cannot be confirmed by reliable biological tests.
The World Health Organization has sounded the alarm as cases rise in the Democratic Republic of Congo and neighboring countries due to the discovery of the new branch and the lack of a vaccine. The goal is therefore to mobilize the entire international community and donors in an effort to establish global coordination to trigger an adequate response.
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