The Delta SARS-CoV-2 variant has a higher viral load than the Beta and the historical variants in nasopharyngeal samples from newly diagnosed COVID-19 patients

Teyssou, Elisa; Delagrèverie, Héloïse; Visseaux, Benoît; Lambert-Niclot, Sidonie; Brichler, Ségolène; Ferré, Valentine Marie; Marot, Stéphane; Jary, Aude; Todesco, Eve; Schnuriger, Aurélie; Ghidaoui, Emna; Abdi, Basma; Akhavan, Sepideh; Houhou‐Fidouh, Nadhira; Charpentier, Charlotte; Morand‐Joubert, Laurence; Boutolleau, David; Descamps, Diane; Cálvez, Vincent; Marcelin, Anne Geneviève; Soulié, Cathia

doi:10.1016/j.jinf.2021.08.027

Cited by 158 publications

(137 citation statements)

References 6 publications

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“…The rise in transmission of the Delta variant appears to be at least in part due to increased viral fitness conferred by mutations in the furin cleavage site that render the virus able to more efficiently enter cells 14,15 . Furthermore, viral RNA levels in samples from people infected with Delta are reported to be higher than those of previous variants with an increased duration of viral shedding 16,17,18,19 . Of particular concern, the levels of RNA in upper respiratory samples from infected individuals are reported to be similar among vaccinated and unvaccinated individuals 18,20 .…”

Section: Main Textmentioning

confidence: 95%

Quantitative measurement of infectious virus in SARS-CoV-2 Alpha, Delta and Epsilon variants reveals higher infectivity (viral titer:RNA ratio) in clinical samples containing the Delta and Epsilon variants

Despres

Mills

Shirley

et al. 2021

Preprint

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Background Novel SARS-CoV-2 Variants of Concern (VoC) pose a challenge to controlling the COVID-19 pandemic. Previous studies indicate that clinical samples collected from individuals infected with the Delta variant may contain higher levels of RNA than previous variants, but the relationship between viral RNA and infectious virus for individual variants is unknown. Methods We measured infectious viral titer (using a micro-focus forming assay) as well as total and subgenomic viral RNA levels (using RT-PCR) in a set of 165 clinical samples containing SARS-CoV-2 Alpha, Delta and Epsilon variants that were processed within two days of collection from the patient. Results We observed a high degree of variation in the relationship between viral titers and RNA levels. Despite the variability we observed for individual samples the overall infectivity differed among the three variants. Both Delta and Epsilon had significantly higher infectivity than Alpha, as measured by the number of infectious units per quantity of viral E gene RNA (6 and 4 times as much, p=0.0002 and 0.009 respectively) or subgenomic E RNA (11 and 7 times as much, p<0.0001 and 0.006 respectively). Conclusion In addition to higher viral RNA levels reported for the Delta variant, the infectivity (amount of replication competent virus per viral genome copy) may also be increased compared to Alpha. Measuring the relationship between live virus and viral RNA is an important step in assessing the infectivity of novel SARS-CoV-2 variants. An increase in the infectivity of the Delta variant may further explain increased spread and suggests a need for increased measures to prevent viral transmission.

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Section: Main Textmentioning

confidence: 95%

Quantitative measurement of infectious virus in SARS-CoV-2 Alpha, Delta and Epsilon variants reveals higher infectivity (viral titer:RNA ratio) in clinical samples containing the Delta and Epsilon variants

Despres

Mills

Shirley

et al. 2021

Preprint

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“…The short-term results of clinical trials of different COVID-19 vaccines demonstrated their high efficacy against symptomatic SARS-CoV-2 infection [4][5][6], later confirmed by the first post-authorization, real-world observations [8]. However, accumulating evidence suggests that this efficacy gradually decreases due to two main factors: (i) a decline in serum anti-spike IgG antibody levels that occurs within a few months following the last vaccination [9,10], and (ii) the emergence of novel SARS-CoV-2 variants, classified as variants of interest (VOIs) and variants of concern (VOCs), such as B.1.617.2 (delta variant), that reveal higher transmissibility and can lead to higher viral loads in the upper respiratory airways [11,12]. The six-month follow-up of participants in the clinical trial of the BNT162b2 vaccine demonstrated that efficacy against infection decreased approx.…”

Section: Introductionmentioning

confidence: 99%

Willingness to Receive the Booster COVID-19 Vaccine Dose in Poland

2021

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COVID-19 vaccinations are essential to mitigate the pandemic and prevent severe SARS-CoV-2 infections. However, the serum antibody levels in vaccinated individuals gradually decrease over time, while SARS-CoV-2 is undergoing an evolution toward more transmissible variants, such as B.1.617.2, ultimately increasing the risk of breakthrough infections and further virus spread. This cross-sectional online study of adult Poles (n = 2427) was conducted in September 2021 (before a general recommendation to administer a booster COVID-19 vaccine dose in Poland was issued) to assess the attitude of individuals who completed the current vaccination regime toward a potential booster dose of the COVID-19 vaccine and identify potential factors that may influence it. Overall, 71% of participants declared willingness to receive a booster COVID-19 dose, with a low median level of fear of receiving it of 1.0 (measured by the 10-point Likert-type scale), which was increased particularly in those having a worse experience (in terms of severity of side effects and associated fear) with past COVID-19 vaccination. The lowest frequency of willingness to receive a booster dose (26.7%) was seen in the group previously vaccinated with Ad26.COV2.S. The majority of individuals vaccinated previously with mRNA vaccines wished to receive the same vaccine, while in the case of AZD1222, such accordance was observed only in 9.1%. The main reasons against accepting a booster COVID-19 dose included the side effects experienced after previous doses, the opinion that further vaccination is unnecessary, and safety uncertainties. Women, older individuals (≥50 years), subjects with obesity, chronic diseases, and pre-vaccination and post-vaccination SARS-CoV-2 infections, and those with a history of vaccination against influenza were significantly more frequently willing to receive a booster COVID-19 dose. Moreover, the majority of immunosuppressed individuals (88%) were willing to receive an additional dose. The results emphasize some hesitancy toward potential further COVID-19 vaccination in the studied group of Poles and indicate the main groups to be targeted with effective science communication regarding the booster doses.

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“…Calls to offer booster doses to the general public have also become frequent in the European countries and the USA [16]. The rationale underlying these calls have been two-fold: (i) observations that serum antibody levels decrease within a few months following the completion of the initial vaccination regime, thus lowering protection against the infection [17][18][19]; and (ii) the emergence of more transmissible SARS-CoV-2 variants such as B.1.617.2 (delta variant), which increases the risk of breakthrough infection and could induce a higher viral load even in vaccinated individuals, at least within the first days after contracting the virus [20][21][22][23][24]. Although the European Medicine Agency stated that "there is no urgent need for the administration of booster doses of vaccines to fully vaccinated individuals" [25] in September 2021, a month later, it concluded that in the case of BNT162b2, "booster doses may be considered at least 6 months after the second dose for people aged 18 years and older" [26]; the agency expressed the same opinion on mRNA-1273 on 25 October 2021 [27].…”

Section: Introductionmentioning

confidence: 99%

COVID-19 Vaccine Boosters: The Good, the Bad, and the Ugly

et al. 2021

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Pursuing vaccinations against COVID-19 brings hope to limit the spread of SARS-CoV-2 and remains the most rational decision under pandemic conditions. However, it does not come without challenges, including temporary shortages in vaccine doses, significant vaccine inequity, and questions regarding the durability of vaccine-induced immunity that remain unanswered. Moreover, SARS-CoV-2 has undergone evolution with the emergence of its novel variants, characterized by enhanced transmissibility and ability to at least partially evade neutralizing antibodies. At the same time, serum antibody levels start to wane within a few months after vaccination, ultimately increasing the risk of breakthrough infections. This article discusses whether the administration of booster doses of COVID-19 vaccines is urgently needed to control the pandemic. We conclude that, at present, optimizing the immunity level of wealthy populations cannot come at the expense of low-income regions that suffer from vaccine unavailability. Although the efficiency of vaccination in protecting from infection may decrease over time, current data show that efficacy against severe disease, hospitalization, and death remains at a high level. If vaccine coverage continues at extremely low levels in various regions, including African countries, SARS-CoV-2 may sooner or later evolve into variants better adapted to evade natural and vaccine-induced immunity, ultimately bringing a global threat that, of course, includes wealthy populations. We offer key recommendations to increase vaccination rates in low-income countries. The pandemic is, by definition, a major epidemiological event and requires looking beyond one’s immediate self-interest; otherwise, efforts to contain it will be futile.

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The Delta SARS-CoV-2 variant has a higher viral load than the Beta and the historical variants in nasopharyngeal samples from newly diagnosed COVID-19 patients

Cited by 158 publications

References 6 publications

Quantitative measurement of infectious virus in SARS-CoV-2 Alpha, Delta and Epsilon variants reveals higher infectivity (viral titer:RNA ratio) in clinical samples containing the Delta and Epsilon variants

Quantitative measurement of infectious virus in SARS-CoV-2 Alpha, Delta and Epsilon variants reveals higher infectivity (viral titer:RNA ratio) in clinical samples containing the Delta and Epsilon variants

Willingness to Receive the Booster COVID-19 Vaccine Dose in Poland

COVID-19 Vaccine Boosters: The Good, the Bad, and the Ugly

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