When we are far from our bases during a hot summer, reading the “general” press sometimes brings us good surprises regarding its scientific content.
I have selected to share with you, in this short blog, some articles that did not make the front page, but that may be of interest to us regarding the current evolution of certain infectious diseases
What is it about?
We are going to talk about Covid-19 which no longer occupies the media space but is still very present. We are learning that one in eight people suffer from symptoms long after the disease has broken out. We also know more about the origin of the pandemic. Monkeypox is making a disturbing appearance in the news because of its relationship to smallpox. Meningococcal B meningitis is on the rise in eastern France. A new virus from China, the Langya henipavirus (LayV) threatens us. Poliomyelitis is back in the news in the United States.
What happens to the outbreak?
SARS-CoV-2 has kept us very busy for over two years. By now (August 20, 2022) we tend to forget that the virus is still with us. Specialists agree that the 7th wave that affected France from June 2022 onwards is about to end as no more epidemic markers are of concern.
The “Scientific Council” ceased its activity on July 31 and was replaced by the “Committee for the monitoring and anticipation of health crises”. At its head, Brigitte Autran, professor of immunology, has been appointed. According to her, “the epidemic is not behind us” and she predicts that an 8th wave could occur in the fall due to the return of cold weather or the appearance of a new variant: the least we can say is that she is not very committed! However, we can moderate our concern, as the population has a good command of barrier measures and vaccination is sufficiently protective, even against the different variants, to limit serious cases.
One in 8 people suffer from long term Covid
On the other hand, a Dutch study published at the beginning of August 2022 and well summarized by the excellent scientific journalist Marc Gozland in Le Monde of August 6, 2022, has shown that one person out of 8 is affected by persistent symptoms more than 3 months after the onset of Covid-19. This is the “long Covid” : tiredness and dyspnea (respiratory discomfort) are the main symptoms of the post-Covid-19 condition but chest pain, agueusia or anosmia are also among the most significant symptoms.
Published in the United Kingdom in June 2022, a survey by the Office for National Statistics (ONS) shows that two million British people report having a long Covid. Of these, 72% report having symptoms for at least 12 weeks, 42% for at least a year and 19% for at least two years. This result shows that post-Covid-19 disease is a significant problem, with an increasing human cost.
The Huanan market of Wuhan
In a study published in science and analyzed by Marc Gozlan in Le Monde on July 29, 2022 it was scientifically shown that the Huanan market in Wuhan was the early epicenter of the Covid-19 pandemic. It also suggests that SARS-CoV-2 probably emerged through the trade of wild live animals in this market. It is not the busiest market in the city (there are 4 in total) but it acted as a supercontaminator.
The 2 lineages A and B
Two viral lineages (B and then A in order of appearance) were responsible for the epidemic. Lineage B was the most prevalent during the epidemic. The researchers analyzed the genetic diversity of SARS-CoV-2 in the early phase of the pandemic. Lineages A and B represent two major families of SARS-CoV-2 as defined by phylogenetic analyses that study the genetic relatedness of viruses.
Combined with epidemiological simulations, this phylodynamic work revealed that the two lineages, present before February 2020, resulted from at least 2 separate transmission events. These 2 lineages appeared 7 days apart, which goes against the hypothesis of the virus escape from the Wuhan P4 laboratory: indeed, this would mean that there would have been a contamination of the market by two distinct viral lineages, coming from the same laboratory about a week apart, which seems unlikely.
In other words, the pandemic most likely began with at least two separate crossings of the species barrier from animal to human in November 2019.
The authors point out that this is not the first time that repeated introductions have led to epidemics or outbreaks of coronaviruses. This has been the case with SARS-CoV-1 and MERS-CoV.
It should be noted that the intermediate hosts that allow bat-hosted viruses to adapt to humans, of which there are a large number of candidates, have not yet been formally identified. Many animal hosts may have harbored the progenitor viruses of SARS-CoV-2, including red foxes, pig badgers, and raccoon dogs (bat predators), all of which were sold live or recently slaughtered in Chinese markets. Cages containing the dogs were even placed on top of cages containing birds.
We have already talked about it in this blog. The Monkeypox virus is very similar to the smallpox virus, but unlike the smallpox virus, it is not spread by aerosols but by pustules on the skin and mucous membranes or droplets of saliva.
According to the latest report issued by Santé publique France on August 18, 2022, 2,889 confirmed cases have been identified in France. One hundred and three thousand doses of vaccine have been delivered to vaccination centers and 43,767 doses injected since the beginning of the vaccination campaign. Although this disease is not strictly a sexually transmitted infection (STI), the vaccine is reserved for contact cases, men who have sex with men reporting multiple sexual partners, and other sex workers.
It seems that the eradication of smallpox from the surface of the globe in 1980 could be at the origin of this Monkeypox epidemic. Indeed, smallpox, which disappeared thanks to an important collective immunity brought by the vaccine (and without any reservoir of the virus other than human), led to the end of vaccination. The world population has therefore lost, little by little, its collective immunization during the forty years that separate us from the end of vaccination. This had 2 important consequences;
- be without immune protection under the threat of a large-scale biological attack with the smallpox virus;
- to have allowed the reappearance of Monkeypox which existed concomitantly to smallpox but whose spread was slowed down by smallpox immunity until the last people vaccinated against smallpox became less numerous (the last vaccines were administered in 1978). This is a good example of the value of herd immunity. But on an individual basis, such an old vaccination must be renewed according to Ouest France of August 5, 2022.
The vaccine used against Monkeypox is the smallpox vaccine Imvanex, the only one licensed to prevent the disease. Produced in Denmark, it is available in France and also in the United States under the name Jynneos® and in Canada under the name Imvamune®. It is a 3rd generation live vaccine. Very recently, Imvanex has been authorized for intradermal injection instead of subcutaneous injection, which allows to inject smaller quantities and to save on doses Huffpost of August 19, 2022. We can also see that the Fake news about vaccines are still current: no the vaccine against Monkeypox is not experimental! 20 minutes of July 25, 2022.
Following the different questions that were asked to the government, one could detect a certain reticence of the authorities to reveal the number and the state of the anti-smallpox vaccine reserves, reserved in case of a biological attack…
Meningococcal meningitis type B
Neisseria meningitidis is a bacterium normally found in the throat and nose of many people (healthy carriers). It can be transmitted by air or saliva. Meningococcal disease does not usually cause any particular illness, but in some cases it can cause very serious illness.
By infecting the meninges (the membranes that envelop the brain and spinal cord), the bacterium causes a disease called meningitis, which is characterized by fever, headaches, photophobia, vomiting, stiff neck, disturbed consciousness, diarrhea.) In some cases, the meningococcus spreads throughout the body, causing septicemia. It then causes a generalized infection of the blood and various organs called purpura fulminans which is frequently fatal. The rapid appearance of one or more red or purplish spots on the body is a sign of seriousness that requires emergency transfer to hospital. The seriousness and the risk of rapid evolution of meningococcal infections require the implementation of an antibiotic treatment as soon as possible. This is done intravenously and is usually continued for 4-7 days.
The best way to prevent the disease is through vaccination.
Twelve serotypes of meningococci have been identified, with types B, C, Y and W135 being the most common in France.
Meningococcal C vaccine; according to the 2021 vaccine schedule, all infants should receive a dose at 5 months of age with meningococcal C vaccine (NEISVAC), followed by a booster dose at 12 months of age (a minimum interval of 6 months must be observed between the 2 doses).
Meningococcal B vaccine; the first group B meningococcal vaccine (BEXSERO) has been available in France since 2014. According to the 2022 vaccination schedule, vaccination against group B meningococcal infections is now recommended with the BEXSERO vaccine for all infants, from the age of 2 months and before the age of 2 years. Since September 2021, a second vaccine against meningococcal B infections is available in France: the TRUMENBA vaccine. It is indicated for adults and children from 10 years of age with an increased risk of infection, such as immunocompromised persons, and in certain specific situations during outbreaks of clustered cases.
Over the past year, a variant of meningococcus B has infected a dozen people in the area of Chambéry and eastern Lyon in a few months and caused one death, Libération, August 12, 2022. This is a very unusual situation, especially since this new variant targets people between the ages of 16 and 24.
According to ARS numbers, there are more than 600 serious meningococcal infections in France each year. The number of deaths related to meningococcal infection is 10% of all cases of global meningitis, according to the ARS. Those most affected by the disease are children under one year of age, those between one and four years of age, and unvaccinated young adults aged 15 to 24 years.
To try to contain the phenomenon, a massive vaccination campaign has been launched in Auvergne-Rhône-Alpes. Fifty-six thousand people at risk around the places concerned have been invited to be vaccinated.
Langya henipavirus (LayV)
A new zoonotic virus called Langya henipavirus (LayV) has been identified. Thirty-five human cases have been identified so far in 2 Chinese provinces between April 2018 and August 2021. Thus, it does not spread rapidly in humans. The virus is common in shrews. Although this virus, originating from bats and passing through an intermediate host, may have been compared to SARS-CoV-2, it is not related to an ongoing epidemic.
The case starts with the publication this August 4 of a study in the New England Journal of Medicine, written by researchers from universities or institutes in China, Singapore and Australia. Their survey, conducted from April 2018 to August 2021 at several Chinese hospitals, focused on patients with acute fever who had recently been exposed to animals. After inspection, the researchers identified a new virus of the genus Henipavirus, named Langya henipavirus.
According to La dépèche.fr on August 21, 2022, most of the infected patients were 60 years old on average and had a high fever. At least half of them also suffered from exhaustion, cough, loss of appetite and a decrease in white blood cells. More than a third of those affected also suffered from liver failure and 8% from kidney failure. No deaths were reported.
According to Prof. François Balloux other Henipaviruses can infect humans. For example, the Nipah virus, which we have already discussed in this blog, is of concern because it is known to be transmitted between humans, but it is so deadly that it has no “pandemic potential”. LayV appears to be much less deadly, but is probably not easily transmitted from human to human. At this point, LayV does not look like a repeat of Covid-19 at all, but it is yet another reminder of the imminent threat caused by the many pathogens circulating in wild and domestic animal populations that have the potential to infect humans.
This disease certainly doesn’t tell you much anymore, it was supposed to have been eradicated in some countries and it has reappeared. Some viral strains have been identified in countries such as the UK, Pakistan, Africa…
According to the Midi Libre of August 10, 2022, the United States is concerned about a possible spread after a case of paralytic polio was confirmed in Rockland County, New York in late June.
The unvaccinated patient was exposed to a viral strain, but because he had not traveled, he was infected in the United States.
Poliomyelitis is a highly contagious disease caused by a virus (poliovirus) that invades the nervous system and can lead to irreversible paralysis in a few hours. This virus is transmitted mainly by fecal-oral route, in particular through contaminated water. The Commissioner of Health of the State of New-York specified that hundreds of infections are to be expected. Based on past polio outbreaks, New Yorkers should be aware that for every case of paralytic polio seen, there may be hundreds more infected.
This information is not very encouraging, but it shows the need to be vaccinated to maintain a high level of immunity. People who are not vaccinated are thus exposed to a risk of contamination.
Recall that since 2015, about 100 cases have been reported worldwide and that before vaccination, the disease affected more than 600,000 children per year.
The common denominator of all this information: vaccination!