Delta variant (Indian): symptoms, vaccination, progression in France

[Variant Covid Delta] In France, the delta variant represents around 30% to 35% of positive tests. To limit the risk of a new wave at the end of the summer, vaccination is essential. Symptoms, contagion, vaccine effectiveness … What we know.

The Delta variant now represents between 30 and 35% of contamination cases at the national level, with significant regional disparities, according to Santé Publique France (bulletin of July 1). He fears a fourth wave this summer. Arnaud Fontanet, epidemiologist at the Institut Pasteur, announced on BFMTV on June 30 that “the Delta variant will represent 80% to 90% of contaminations at the end of August”, justifying this forecast by the fact that there is, in France, a two-month lag with Great Britain.

The Landes prefecture has extended health restrictions until July 6 inclusive in the department due to the active circulation of the Delta variant.

As several European countries gradually lifted their health measures, the European branch of the World Health Organization (WHO) said the number of Covid-19 cases had increased by 10% last week in Europe. This is “due to the increase in mingling, travel, gatherings and the relaxation of social restrictions.”

In Portugal, which surpassed the 2,000 new cases mark in 24 hours, the highest level recorded since mid-February, the Delta variant of the coronavirus has become predominant. The authorities have therefore decided to re-establish a night curfew from Friday, July 2, in 45 municipalities including Lisbon. In Russia, the authorities announced the return of teleworking for 30% of employees due to the resurgence of cases. Berlin has also added Portugal and Russia to its list of “variant” countries, which prohibits most arrivals from these two countries. In the UK, where it first appeared in April, the Delta variant is predominant.


Symptoms of the Delta variant

Scientists believe that symptoms would remain “classic” and mild, similar to a “bad cold”.

Headache, sore throat, runny nose … These mild symptoms are among the most common among young Britons suffering from the Covid-19 Delta variant, according to a British study (Zoe Covid) which is based on data collected – via a participatory application – from infected people.

“Since the beginning of May, we have looked at the most common symptoms for all app users, and they are not the same as before, comments Tim Spector, professor of genetic epidemiology at King’s College London at Guardian. From now on, the number one symptom is headache… followed by sore throat, runny nose and fever.”

Unlike the classic form of Covid, cough does not appear as a main symptom, as well as the loss of taste and smell. Indeed, it is the 5th symptom notified via the application. As for ageusia and anosmia, they are not even in the top 10.

According to the professor, the resemblance to the common cold can be problematic because “people may think that they only have a simple seasonal cold, and continue to meet up to party… ”.

Asked in Le Figaro dated April 20, Anurag Agarwal, director of the Delhi Institute of Genomics and Integrative Biology, also observed that patients complained of “headache, nasal congestion, sore throat, muscle pain.”

The Delta variant in France

The proportion of the Delta variant, although in the minority, is increasing, observes Public Health France in its latest epidemiological bulletin. As of June 29, the three regions with the highest number of confirmed Delta variant cases were Nouvelle-Aquitaine (111), Île-de-France (82) and Provence-Alpes-Côte d’Azur (63 ) and all regions reported at least one case of the Delta variant.

According to the government, he represents at the beginning of July, 30 to 35% of contaminations in France.

This estimate is obtained from screening tests carried out after a positive PCR or antigen test. Their interest? They make it possible to follow the diffusion of variants, by identifying 3 monitored mutations: E484K (carried by the beta or South African and gamma or Brazilian variants), E484Q and L452R (the delta variant which circulates in France presents only the L452R mutation).

In week 25 (week of June 21), the E484K, E484Q and L452R mutations were detected in respectively 24%, 0.8% and 20.5% of the positive samples screened, details Public Health France in its latest epidemiological bulletin.

In addition, the preliminary results of the Flash # 11 survey of June 8, 2021 show that the variant of concern Alpha remained predominant, but decreasing, and that the share of variants carrying the E484K or E484Q mutations remained stable at 10.4%. On the other hand, the Delta variant increased sharply from 0.8% in Flash # 10 to 7.0% in Flash # 11, with a strong geographic heterogeneity.

In the Landes, the Delta variant represents around 50% of the positive cases detected.

Consequently, the Minister of Health called on the French to remain vigilant, while recalling the maintenance for the moment of the wearing of the mask outside.

Vaccination is more than ever essential. From the British experience, the vaccination is 90% effective against the Delta variant after two doses, regardless of the vaccine.

The delta variant is progressing in the Landes

The Delta variant is largely in the Landes department. His presence now represents 50% of positive cases. This rate is however to be put into perspective due to the fact that it is calculated on a number of cases which remains very low (23 cases on June 23), specifies the ARS Nouvelle-Aquitaine.

According to ARS Nouvelle-Aquitaine (press release of July 2), “the circulation of the virus is still declining, with an incidence rate falling below the attention threshold”.

In fact, in week 25 (from June 21 to June 27), the incidence rate is 15.2 / 100,000 inhabitants against 20.6 / 100,000 inhabitants in week 24. It remains so on below the attention threshold, set at 20/100 000 inhabitants. As for the positivity rate, it remains at 0.8%.

The ARS also stresses that the vaccination is effective with a reduction in the risk of severe form of 70% after one injection and more than 90% after two injections.

Vaccination therefore remains the best weapon. And this all the more so in New Aquitaine, where the virus has circulated little, the natural immunity, acquired after an infection with Covid-19, remains low and must be compensated by a high vaccination coverage.

As of June 30, 3,342,197 Neo-Aquitaine had received at least one dose of vaccine (55.7%) and 2,212,360 had received both doses (36.9%).

“Nouvelle-Aquitaine is the 2nd metropolitan region in terms of one-dose vaccination coverage (55.7%), tied with Normandy (52.9%) and after Brittany (56.7%)”, rejoices the ‘ARS. Regarding the complete vaccination schedule (2 doses of vaccine), New Aquitaine is in 2nd position (36.9%) after Corsica (41.0%).

“If the vaccination coverage is now very high among the elderly, especially those residing in nursing homes, it is still insufficient among young people who are particularly concerned by the population gatherings during the summer”, further underlines the ARS New Aquitaine.

In the United Kingdom, the Indian variant (Delta) took over the English variant (Alpha)

England decided on June 14 to postpone the last stage of deconfinement on English territory by 4 weeks. The Delta variant has indeed become the majority (90% of contaminations), putting the epidemic on an “upward trajectory”, commented Olivier Véran on Tuesday, June 15. And this while the country has a “vaccination coverage rate higher than ours” and was “very low in terms of circulation of the virus”.

Official data from Public Health England published on June 4 shows that contamination is on the increase, especially among young people, with an R again above 1 (1.44). This Indian variant could be at least 40% more contagious than the English variant (or Alpha) and would lead to a risk of hospitalization up to 2.5 times higher.

As a precaution against the Indian variant of the coronavirus which is progressing in the United Kingdom, France decided on Wednesday May 26 to set up a compulsory isolation for all travelers from Great Britain.

Variant delta and vaccination

The variant India Delta B.1.617 of its scientific name, was identified in India in 2020. This variant in fact combines two mutations on the Spike protein, which is why it is called “double mutant”: mutation E484Q (also detected in the Californian variant) and the mutation L452R (present in the Brazilian variant). Thanks to these mutations, this virus is able to attack cells better. The one that is most frequently encountered in France and in Europe does not present the E484Q mutation.

It includes three sublines (B.1.617.1, B.1.617.2 and B.1.617.3) which differ slightly in terms of mutations of interest. It’s the B.1.617.2 (Delta), which is classified as “VOC” because of data suggesting an increased transmissibility compared to the reference strains and a possible impact in terms of immune escape post-vaccination (reduced efficacy in particular in the event of incomplete vaccination).

  • The Delta variant is more contagious

This variant is associated with a increased transmissibility of the virus (between 40 and 60%) due to the L452R mutation.

  • Vaccine efficacy is lower against the risk of contamination, but it is preserved against the risk ofhospitalization (provided you have a complete vaccination schedule):

According to UK government data, the two doses of vaccine are only effective between 55% and 71% in preventing Delta variant infections (which explains why contaminations continue to rise) but are effective at 90% to prevent hospitalizations and 96% to reduce mortality.

On the other hand, the efficacy of the vaccine (Astra Zeneka or Pfizer) with regard to the risk of hospitalization in the event of infection with the Delta variant is lower after a single dose (75%). From where the importance of receiving two doses of the vaccine for the best possible protection.

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