VARIANT BA.5. The number of Covid-19 cases continues to increase in France, in particular because of the BA.4 and BA.5 variants. What are the symptoms of these variants? Will their spread be slowed down by vaccination?
[Mis à jour le 1er juillet 2022 à 22h22] The BA.4 and BA.5 variants of Covid-19 contribute to the increase in cases in France. Thus, during its epidemiological update on Thursday June 30, the Public Health France organization indicates that the circulation of Covid is intensifying in France. It emphasizes in particular that the BA.5 variant is becoming the majority since it is gradually replacing BA.2.
With the increase in cases, Public Health France recommends continuing to apply barrier gestures and keeping the mask in the presence of fragile people, in closed spaces, in transport or during large gatherings. In addition, the health organization notes that the number of hospitalizations is rising sharply, as well as the number of deaths. Is this increase due to the BA.4 and BA.5 variants?
What do the BA.4 and BA.5 variants of Covid correspond to?
BA.4, BA.5… Designations worthy of an administrative form to fill out. However, it is indeed one of the many names of the disease of the coronavirus. In reality, the BA.4 and BA.5 variants are sub-variants of the Omicron variant, which imposed itself in France during the year 2022, as the scientists indicated. Concretely, it is a mutation of the virus in certain aspects, without a really significant difference compared to the variant being detected. It is a mutation of mutation.
As for the name, the two letters and the number assigned to them correspond to a specific scientific classification. These two sub-variants have been classified in the “variants of interest” by theWorld Health Organization (WHO).
What is the origin of the BA.4 and BA.5 variants?
If the BA.4 and BA.5 sub-variants are now very present in France, it is far from France that they find their origin. BA.4 and BA.5 were indeed detected for the first time in South Africa, as early as November. However, there is nothing to confirm that they appeared in this country at that time. It was only thanks to the sequencing carried out by local scientists that they could be isolated in the fall, without providing any insight into their exact origin.
What are the symptoms of the BA.4 and BA.5 variants?
This has been the big question since the appearance of the Covid-19 pandemic: how do you know if you have contracted the virus or not? In a report from Public Health France published in mid-June, symptoms of the BA.4 and BA.5 subvariants of Covid were partly detailed and distinguished from earlier variants of the virus. This analysis, conducted using a questionnaire with 73 cases of infection with the BA.4 variant (67 confirmed cases and 6 possible cases) and 228 cases of infection with the BA.5 variant (210 confirmed cases and 18 possible cases), establishes that “the most frequent clinical signs were asthenia/fatigue (75.7%), cough (58.3%), fever (58.3%), headache (52.1%) and runny nose (50.7%)”.
“The cases of BA.4 and BA.5 presented more frequently than the cases of BA.1 a runny nose” writes the public health agency., but also “nausea / vomiting”, sometimes diarrhea, ageusia (loss of taste) and anosmia (loss of sense of smell). Well-known Covid symptoms, yet less frequent since the appearance of Omicron. “The median duration of signs was seven days […], which is longer than for the cases of BA.1 (four days)”, also points out Public Health France, which concludes: “the probability of presenting anosmia and ageusia, but also nausea, vomiting and diarrhea was higher for the cases of BA.4/BA.5 compared to those of BA.1. BA.4/BA.5 cases also reported longer duration of clinical signs.”
Here is the list of the most frequent symptoms of the BA.4 and BA.5 subvariants of Covid, established at this stage by Public Health France (from 288 cases reported):
- Asthenia/fatigue: 75.7% (against 56.2% for sub-variant BA.1)
- Cough: 58.3% (against 50.9%)
- Fever: 58.3% (against 47.7%)
- Headaches (headaches): 52.1% (against 43.1%)
- Runny nose: 50.7% (against 26.3%)
- Myalgia (muscle pain): 41.0% (against 38.1%)
- Sore throat: 39.6% (against 31.3%)
- Nausea/Vomiting: 18.4% (vs. 7.1%)
- Feeling of fever: 18.1% (against 12.5%)
- Ageusia: 17.0% (against 8.9%)
- Anosmia: 16.7% (against 8.2%)
- Shortness of breath: 15.3% (vs. 8.5%)
- Diarrhea: 15.3% (vs. 6.0%)
- Dyspnea: 7.6% (against 2.5%)
- Colds: 1.0% (vs. 0.4%)
- Dizziness: 0.7% (against 0.4%)
Are the BA.4 and BA.5 variants more contagious?
While the Omicron variant had been presented as dangerous by the authorities given its particularly transmissible nature, its BA.4 and BA.5 sub-variants would also have the ability to be transmitted easily between men, according to the first analyzes, commented on by Health public France. However, these calculations are based on a small number of cases and there is a high degree of uncertainty. Analyzes are underway to further assess the transmissibility of these subvariants, including whether or not they manage to evade the vaccine.
the gradual replacement of BA.2 by BA.5, which represented less than a quarter of the cases in the “Flash” surveys of Public Health France at the beginning of June and now exceeds 50% is an unmistakable sign. These “diffusion dynamics” from BA.2 to BA.5 “suggest […] that they possess an advantage over BA.2,” writes the health agency. She cites work carried out in May 2022 by its Anglo-Saxon counterpart (the “UK Health Security Agency” or UKHSA), who suggest that the growth rates of BA.4 and BA.5 would be “similar to those of BA.2 compared to BA.1”. However, we know that BA.2 very quickly supplanted Omicron’s BA.1 sub-variant at the very beginning of last spring.
How dangerous are the BA.4 and BA.5 variants?
For the time being, scientists lack hindsight as to the intrinsic dangerousness of the two BA.4 and BA.5 sub-variants. However, the first elements communicated by Public Health France indicate that no “increase in severity” has been observed between these sub-variants and their predecessors, mainly affecting people at risk, as for the other variants of Covid.
In its report of mid-June, Public Health France writes that “the data accumulated in several countries did not observe an increase in severity associated with BA.4 and BA.5”. This time is summoned a European Center for Disease Prevention and Control (ECDC) report of June 13 which reports no signal of a more dangerous infection. As a reminder, the emergence of Omicron at the end of 2021 coincided with a significant decrease in the hospitalization rate compared to the other variants, in particular the Delta variant. But SPF warns: “This lower severity is partly driven by pre-existing immunity in the population, which remains protective against severe forms. A more recent study, conducted in the United States (see the study published in The Lancet – Editor’s note) estimated, after correction of cofactors (such as the date of the test, age, sex, ethnicity, region of residence, vaccination status and history of infection), the risks of hospitalization and almost identical deaths between the Omicron wave and previous waves, concluding that “intrinsic severity of Omicron is similar to previous variants.”
The observation of epidemic waves caused by the BA and BA.5 variants of Covid in South Africa and Portugal lately augurs well for a short wave and with a “limited hospital impact”.
How effective are vaccines against the BA.4 and BA.5 variants?
While calls to receive a new booster dose of the vaccine against Covid have multiplied in recent days, the effectiveness of the vaccines against the BA.4 and BA.5 sub-variants seems uncertain. A study published in The New England Journal of Medicine explains that “BA.4 and BA.5 significantly escape neutralizing antibodies induced by both vaccination and infection.” Antibodies generated by the infection are also lower than with the other variants. “Suggesting that the Omicron variant has continued to evolve with an increased capacity for immune escape,” it adds. New adapted vaccines should thus see the light of day. Pfizer and Moderna are in any case working in this direction.
In the meantime, the French authorities, through Public Health France, once again continue to emphasize that the “estimates of vaccine efficacy (VE) are all in favor of limited protection against infection, but [que] protection remains very high against serious forms, especially with a booster dose”. The President of the Scientific Council Jean-François Delfraissy indicated Thursday, June 30 at the microphone of RTL that it was necessary to be vaccinated with the 4th dose “now, without waiting for September October”, for the over 60s and people at risk. According to him, the vaccines remain effective against the severe forms caused by the BA.5 variant.