Insertion and deletion mutations preserved in SARS-CoV-2 variants.

The insertion/deletion (indel) mutation profiles of SARS-CoV-2 variants, including Omicron, remain unclear. We compared whole-genome sequences from various lineages and used preserved indels to infer the ancestral relationships between different lineages. Thirteen indel patterns from twelve sites were seen in ≥ 2 sequences; six of these sites were located in the N-terminal domain of the viral spike gene. Preserved indels in the coding regions were also identified in the non-structural protein 3 (Nsp3), Nsp6, and nucleocapsid genes. Seven of the thirteen indel patterns were specific to the Omicron variants, four of which were observed in BA.1, making it the most mutated variant. Other preserved indels observed in the Omicron variants were also seen in Alpha and/or Gamma, but not Delta, suggesting that Omicron is phylogenetically more proximal to Alpha. We demonstrated distinct profiles of preserved indels among SARS-CoV-2 variants and sublineages, suggesting the importance of indels in viral evolution.

Trinucleotide Substitutions at Two Locations in the SARS-CoV-2 Nucleocapsid (N) Gene.

The genomes of sarbecoviruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), incorporate mutations with short sequence exchanges based on unknown processes. Currently, the presence of such short-sequence exchanges among the genomes of different SARS-CoV-2 lineages remains uncertain. In the present study, multiple SARS-CoV-2 genome sequences from different clades or sublineages were collected from an international mass sequence database and compared to identify the presence of short sequence exchanges. Initial screening with multiple sequence alignments identified two locations with trinucleotide substitutions, both in the nucleocapsid (N) gene. The first exchange from 5'-GAT-3' to 5'-CTA-3' at nucleotide positions 28,280-28,282 resulted in a change in the amino acid from aspartic acid (D) to leucine (L), which was predominant in clade GRY (Alpha). The second exchange from 5'-GGG-3' to 5'-AAC-3' at nucleotide positions 28,881-28,883 resulted in an amino acid change from arginine and glycine (RG) to lysine and arginine (KR), which was predominant in GR (Gamma), GRY (Alpha), and GRA (Omicron). Both trinucleotide substitutions occurred before June 2020. The sequence identity rate between these lineages suggests that coincidental succession of single-nucleotide substitutions is unlikely. Basic local alignment search tool sequence search revealed the absence of intermediating mutations based on single-base substitutions or overlapping indels before the emergence of these trinucleotide substitutions. These findings suggest that trinucleotide substitutions could have developed via an en bloc exchange. In summary, trinucleotide substitutions at two locations in the SARS-CoV-2 N gene were identified. This mutation may provide insights into the evolution of SARS-CoV-2.

Variable number tandem repeats of a 9-base insertion in the N-terminal domain of severe acute respiratory syndrome coronavirus 2 spike gene.

Introduction: The world is still struggling against the pandemic of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in 2022. The pandemic has been facilitated by the intermittent emergence of variant strains, which has been explained and classified mainly by the patterns of point mutations of the spike (S) gene. However, the profiles of insertions/deletions (indels) in SARS-CoV-2 genomes during the pandemic remain largely unevaluated yet. Methods: In this study, we first screened for the genome regions of polymorphic indel sites by performing multiple sequence alignment; then, NCBI BLAST search and GISAID database search were performed to comprehensively investigate the indel profiles at the polymorphic indel hotspot and elucidate the emergence and spread of the indels in time and geographical distribution. Results: A polymorphic indel hotspot was identified in the N-terminal domain of the S gene at approximately 22,200 nucleotide position, corresponding to 210-215 amino acid positions of SARS-CoV-2 S protein. This polymorphic hotspot was comprised of adjacent 3-base deletion (5'-ATT-3'; Spike_N211del) and 9-base insertion (5'-AGCCAGAAG-3'; Spike_ins214EPE). By performing NCBI BLAST search and GISAID database search, we identified several types of tandem repeats of the 9-base insertion, creating an 18-base insertion (Spike_ins214EPEEPE, Spike_ins214EPDEPE). The results of the searches suggested that the two-cycle tandem repeats of the 9-base insertion were created in November 2021 in Central Europe, whereas the emergence of the original one-cycle 9-base insertion (Spike_ins214EPE) would date back to the middle of 2020 and was away from the Central Europe. The identified 18-base insertions based on 2-cycle tandem repeat of the 9-base insertion were collected between November 2021 and April 2022, suggesting that these mutations could not survive and have been already eliminated. Discussion: The GISAID database search implied that this polymorphic indel hotspot to be with one of the highest tolerability for incorporating indels in SARS-CoV-2 S gene. In summary, the present study identified a variable number of tandem repeat of 9-base insertion in the N-terminal domain of SARS-CoV-2 S gene, and the repeat could have occurred at different time from the insertion of the original 9-base insertion.

Acute Adverse Events at a Mass Vaccination Site after the Third and Fourth COVID-19 Vaccinations in Japan.

The third and fourth doses of the vaccine against coronavirus disease 2019 (COVID-19) were widely administered in Japan since December 2021. Currently, however, data are scarce regarding acute adverse events with the third and fourth doses. The present study reports the profiles of acute adverse events after the third and fourth COVID-19 vaccine doses, seen at the site of a mass vaccination center in Japan. Between December 2021 and July 2022, 267,515 individuals received the third, and 32,934 received the fourth COVID-19 vaccine dose at the mass vaccination center, of whom 442 recipients of the third (0.19%), and 22 recipients of the fourth (0.07%) dose reported acute adverse events and were examined by doctors on site. The most common diagnosis was vasovagal syncope/presyncope (incidence: 0.01-0.10%), followed by other miscellaneous complaints, acute allergic reactions (0.05-0.005%), and anaphylaxis (< 0.005%). Vasovagal syncope/presyncope occurred most frequently in recipients in those in their 20s, whereas acute allergic reactions were most frequent in those in their 40s. Both reactions were more frequent in women than men. The peak occurrence of vasovagal syncope/presyncope was earlier than 15 min after the injection, whereas that of acute allergic reaction was later than 15 min after the injection. The incidence of acute allergic reactions appeared to differ between various vaccine manufacturers, whereas that of vasovagal syncope/presyncope did not. These real-world data may benefit the safe and efficient implementation of mass vaccination campaigns for citizens who want to receive COVID-19 vaccines now and in the future.

Insertion/deletion hotspots in the Nsp2, Nsp3, S1, and ORF8 genes of SARS-related coronaviruses.

The genome of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) contains many insertions/deletions (indels) from the genomes of other SARS-related coronaviruses. Some of the identified indels have recently reported to involve relatively long segments of 10-300 consecutive bases and with diverse RNA sequences around gaps between virus species, both of which are different characteristics from the classical shorter in-frame indels. These non-classical complex indels have been identified in non-structural protein 3 (Nsp3), the S1 domain of the spike (S), and open reading frame 8 (ORF8). To determine whether the occurrence of these non-classical indels in specific genomic regions is ubiquitous among broad species of SARS-related coronaviruses in different animal hosts, the present study compared SARS-related coronaviruses from humans (SARS-CoV and SARS-CoV-2), bats (RaTG13 and Rc-o319), and pangolins (GX-P4L), by performing multiple sequence alignment. As a result, indel hotspots with diverse RNA sequences of different lengths between the viruses were confirmed in the Nsp2 gene (approximately 2500-2600 base positions in the overall 29,900 bases), Nsp3 gene (approximately 3000-3300 and 3800-3900 base positions), N-terminal domain of the spike protein (21,500-22,500 base positions), and ORF8 gene (27,800-28,200 base positions). Abnormally high rate of point mutations and complex indels in these regions suggest that the occurrence of mutations in these hotspots may be selectively neutral or even benefit the survival of the viruses. The presence of such indel hotspots has not been reported in different human SARS-CoV-2 strains in the last 2 years, suggesting a lower rate of indels in human SARS-CoV-2. Future studies to elucidate the mechanisms enabling the frequent development of long and complex indels in specific genomic regions of SARS-related coronaviruses would offer deeper insights into the process of viral evolution.

Reports of acute adverse events in mRNA COVID-19 vaccine recipients after the first and second doses in Japan.

Mass vaccination against coronavirus disease 2019 (COVID-19) is ongoing in many countries worldwide. This study reports the occurrence of acute adverse events among vaccine recipients at a mass vaccination center in Japan. Between August and November 2021, approximately 130,000 individuals received two mRNA vaccine doses (mRNA-1273; Moderna) at the vaccination center. Acute adverse events at the site were observed in 1.1% of the recipients after the first dose and in 0.4% of the recipients after the second dose. The most common event was vasovagal syncope/presyncope, followed by acute allergic reactions. The occurrence rate of vasovagal syncope/presyncope was highest in the young population of those aged 16-29 years, but such age-dependency was not apparent in acute allergic reactions. Both symptoms were more prevalent in women than in men. Vasovagal syncope/presyncope occurred mainly within 20 min of the injection, whereas nearly half of the episodes of acute allergic reactions occurred after 20 min. The vaccine being injected while the recipient was in the supine position effectively reduced the occurrence of vasovagal syncope/presyncope. In summary, the suggested risk factors for vasovagal syncope/presyncope included a young age and female sex. The vaccine being injected while the recipient was in the supine position would reduce the risk of vasovagal syncope/presyncope.

COVID-19-Related Symptoms during the SARS-CoV-2 Omicron (B.1.1.529) Variant Surge in Japan.

The exact profiles of the clinical symptoms related to the SARS-CoV-2 Omicron variant (B.1.1.529) remain largely uncertain. Therefore, this study aimed to clarify the clinical manifestations of infection with this variant. We enrolled individuals who were tested by quantitative nasopharyngeal swab reverse transcription-polymerase chain reaction (RT-PCR) test at a large screening center in a city of Japan during the B.1.1.529 Omicron variant wave between January and May 2022, after contact with COVID-19 patients. Swab tests were planned to be performed approximately 4-5 days after contact. The presence of COVID-19-related symptoms was assessed at the swab test site. Among the 2,507 enrolled individuals, 943 (37.6%) were RT-PCR test-positive and 1,564 (62.4%) were test-negative. Among the 943 PCR test-positive participants, the prevalence of the symptoms was as follows: 47.3% with cough, 32.9% with sore throat, 18.4% with fatigability, 12.7% with fever of ≥ 37.5℃, 9.9% with dyspnea, 2.1% with dysosmia, and 1.4% with dysgeusia. The prevalence of cough, sore throat, dyspnea, and fatigability was higher among adults aged ≥ 18 years than among children and adolescents. The prevalence of dysosmia and dysgeusia remarkably decreased during the Omicron wave (1-3%) compared to during the pre-Omicron variant waves (15-25%). In summary, common COVID-19-related symptoms during the Omicron variant wave included cough and sore throat, followed by fatigability, fever, and dyspnea. The prevalence of most of these symptoms was higher in adults than in non-adults. The prevalence of dysosmia and dysgeusia remarkably decreased with the Omicron variant than with pre-Omicron variants.

Effectiveness of third vaccine dose for coronavirus disease 2019 during the Omicron variant pandemic: a prospective observational study in Japan.

The administration of a third booster dose of messenger ribonucleic acid (mRNA) vaccines against coronavirus disease 2019 (COVID-19) has progressed worldwide. Since January 2022, Japan has faced a nationwide outbreak caused by the Omicron variant, which occurred simultaneously with the progression of mass vaccination with the third booster dose. Therefore, this study evaluated the effectiveness of the third dose of vaccine by reverse transcription-polymerase chain reaction (RT-PCR) test using nasopharyngeal swab samples from adults aged ≥ 18 years tested after having close contact with COVID-19 cases between January and May 2022. Participants who completed only one dose were excluded from the study. Among the 928 enrolled participants, 139 had never been vaccinated, 609 had completed two doses, 180 had completed three doses before the swab test, and the overall RT-PCR test positivity rate in each group was 48.9%, 46.0%, and 32.2%, respectively. The vaccine effectiveness of the third dose to prevent infection after close contact was approximately 40% (95% confidence interval: 20-60%), which was the highest at 10-70 days after receiving the third dose. In conclusion, the effectiveness of the three-dose mRNA COVID-19 vaccine after close contact during the Omicron outbreak is approximately 40%.

Refractory Chest Pain in Mild to Moderate Coronavirus Disease 2019 Successfully Treated with Saikanto, a Japanese Traditional Medicine.

Coronavirus disease 2019 (COVID-19) causes a variety of pain symptoms in the acute phase. Severe chest pain suddenly occurs even without abnormalities on examination and is sometimes refractory to analgesics. Such pain is a clinical concern in care facilities with limited resources, and this is the first report on the use of saikanto for its treatment. In Miyagi Prefecture, Japan, COVID-19 patients with mild symptoms were admitted to a hotel that operated as an isolation facility, and their symptoms were observed. In this article, we report four cases in which chest pain comorbid with mild to moderate COVID-19 was successfully treated with saikanto, a traditional Japanese (Kampo) medicine. The patients presented with chest pain and underwent medical examination at the facility. Two patients had severe chest pain refractory to acetaminophen. Critical cardiopulmonary diseases were ruled out in all the patients, and three patients had features of pneumonia on chest radiograph. Medications, including saikanto, were administered to the patients. The patients' chest pain and other symptoms improved 1-4 days after the administration of saikanto, and they left the care facility without hospitalization. The cause of the chest pain experienced by these patients is unclear, but we speculate that it could be minimal pleural inflammation or neuropathy. Previous pharmacological studies have suggested anti-inflammatory and analgesic properties of the crude drugs that constitute saikanto. This case report suggests that saikanto could be a treatment option for chest pain refractory to analgesics in patients with mild to moderate COVID-19.

Comparison of Insertion, Deletion, and Point Mutations in the Genomes of Human Adenovirus HAdvC-2 and SARS-CoV-2.

Virus genome mutation profiles with insertion, deletion, and point mutations have recently been revealed to differ remarkably between viruses. In RNA viruses like human coronaviruses or influenza viruses, genome samples collected over two to three decades usually show point mutations in 10-20% of the bases, while the rate of insertion and/or deletion mutations (indels) largely depends on the virus. This study evaluates the mutation profiles of DNA viruses by comparing a recently sampled genome of human adenovirus species C type 2 (isolate SG06/HAdvC2/2016) with a genome of the same species sampled in the 1970s. It was found insertions of 23 bases at seven sites and deletions of 22 bases at nine sites. The longest indels were 6-base insertions in E2B and L4. All indels in the coding regions were in-frame mutations with base lengths in multiples of three. In the non-coding regions, the lengths of the indels ranged from 1-4 consecutive bases. Long indels with more than 10 consecutive bases, which comprise nearly half of indels in the SARS-CoV-2 genome, were absent. In other sites, the point mutation rate was approximately 0.3%, which was significantly lower than in RNA viruses. In summary, the estimated point mutation rate in human adenovirus species C type 2 (HAdvC-2) was over 10 times lower than in RNA viruses. Unlike the relatively long indels in the SARS-CoV-2 genome, the indels in HAdvC-2 were short, with 6 or fewer consecutive bases.

A simulation of geographic distribution for the emergence of consequential SARS-CoV-2 variant lineages.

The coronavirus disease 2019 (COVID-19) pandemic has been facilitated by the intermittent emergence of consequential variant strains. This study evaluated the geographic disproportionality in the detection of consequential variant lineages across countries. As of November 2021, a total of 40 potentially consequential SARS-CoV-2 variant lineages have been identified. One-hundred repeated simulations that randomly produced consequential variants from overall COVID-19 cases worldwide were performed to evaluate the presence of geographical disproportion in the occurrence of consequential variant outbreaks. Both the total number of reported COVID-19 cases and the number of reported genome sequences in each country showed weak positive correlations with the number of detected consequential lineages in each country. The simulations suggest the presence of geographical disproportion in the occurrence of consequential variant outbreaks. Based on the random occurrence of consequential variants among COVID-19 cases, identified consequential variants occurred more often than expected in the United Kingdom and Africa, whereas they occurred less in other European countries and the Middle East. Simulations of the occurrence of consequential variants by assuming a random occurrence among all COVID-19 cases suggested the presence of biogeographic disproportion. Further studies enrolling unevaluated crucial biogeographical factors are needed to determine the factors underlying the suggested disproportionality.

Insertion-and-Deletion Mutations between the Genomes of SARS-CoV, SARS-CoV-2, and Bat Coronavirus RaTG13.

The evolutional process of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) development remains inconclusive. This study compared the genome sequences of severe acute respiratory syndrome coronavirus (SARS-CoV), bat coronavirus RaTG13, and SARS-CoV-2. In total, the genomes of SARS-CoV-2 and RaTG13 were 77.9% and 77.7% identical to the genome of SARS-CoV, respectively. A total of 3.6% (1,068 bases) of the SARS-CoV-2 genome was derived from insertion and/or deletion (indel) mutations, and 18.6% (5,548 bases) was from point mutations from the genome of SARS-CoV. At least 35 indel sites were confirmed in the genome of SARS-CoV-2, in which 17 were with ≥10 consecutive bases long. Ten of these relatively long indels were located in the spike (S) gene, five in nonstructural protein 3 (Nsp3) gene of open reading frame (ORF) 1a, and one in ORF8 and noncoding region. Seventeen (48.6%) of the 35 indels were based on insertion-and-deletion mutations with exchanged gene sequences of 7-325 consecutive bases. Almost the complete ORF8 gene was replaced by a single 325 consecutive base-long indel. The distribution of these indels was roughly in accordance with the distribution of the rate of point mutation rate around the indels. The genome sequence of SARS-CoV-2 was 96.0% identical to that of RaTG13. There was no long insertion-and-deletion mutation between the genomes of RaTG13 and SARS-CoV-2. The findings of the uneven distribution of multiple indels and the presence of multiple long insertion-and-deletion mutations with exchanged consecutive base sequences in the viral genome may provide insights into SARS-CoV-2 development. IMPORTANCE The developmental mechanism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains inconclusive. This study compared the base sequence one-by-one between severe acute respiratory syndrome coronavirus (SARS-CoV) or bat coronavirus RaTG13 and SARS-CoV-2. The genomes of SARS-CoV-2 and RaTG13 were 77.9% and 77.7% identical to the genome of SARS-CoV, respectively. Seventeen of the 35 sites with insertion and/or deletion mutations between SARS-CoV-2 and SARS-CoV were based on insertion-and-deletion mutations with the replacement of 7-325 consecutive bases. Most of these long insertion-and-deletion sites were concentrated in the nonstructural protein 3 (Nsp3) gene of open reading frame (ORF) 1a, S1 domain of the spike protein, and ORF8 genes. Such long insertion-and-deletion mutations were not observed between the genomes of RaTG13 and SARS-CoV-2. The presence of multiple long insertion-and-deletion mutations in the genome of SARS-CoV-2 and their uneven distributions may provide further insights into the development of the virus.

Prolonged Diarrhea Following COVID-19 Vaccination: A Case Report and Literature Review.

Vaccination against coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is currently underway across countries worldwide. However, the prevalence and characteristics of prolonged adverse events lasting for several months after receiving the vaccine remain largely unknown. We herein report a 46-year-old woman with prolonged diarrhea and vomiting after receiving the BNT162b2 mRNA vaccine for COVID-19. She had no notable medical history, including that of gastrointestinal diseases. She developed vomiting several hours after receiving the first vaccine dose and further developed severe diarrhea after 7 days. Several days after the second vaccine dose, her condition deteriorated, unrelieved by symptomatic therapies, including anti-diarrheal drugs. Abdominal computed tomography (CT) revealed inflammatory changes in the entire segment of the small intestine with wall thickening. The upper and lower gastrointestinal and capsule endoscopies were unremarkable. The patient's symptoms persisted for more than 6 months after the second vaccine dose. A Vaccine Adverse Event Reporting System (VAERS) database search suggested that diarrhea is observed in approximately 3% of all vaccine recipients, but a literature review indicated that prolonged gastrointestinal symptoms lasting for several months is very rare. In summary, a case of prolonged unexplained gastrointestinal symptoms, possibly based on inflammatory changes in the small intestine, is described. A literature search revealed that this type of manifestation is very rare, and further evidence is needed to determine the causality between vaccination and gastrointestinal symptoms.

Coronavirus disease 2019 transmission and symptoms in young children during the severe acute respiratory syndrome coronavirus 2 Delta variant and Omicron variant outbreaks.

OBJECTIVE: Little is known about the transmission of coronavirus disease 2019 (COVID-19) in young children. This study aimed to clarify the risk of COVID-19 transmission among this population. METHODS: Between July 2020 and April 2022, 1660 0 to 3-year-old children underwent a nasopharyngeal swab for later reverse transcription-polymerase chain reaction testing at a mass screening test center in Japan. Their disease transmission rate and clinical symptoms were evaluated according to the predominant variant strains of that season. RESULTS: The secondary transmission rate after close contact of the Delta B.1.617.2 (17.4%) and Omicron B.1.1.529 (39.2%) variants was significantly higher than that of the conventional strains (B.1.1.284 and B.1.1.214; 4.5%) during the pandemic. The increased transmissibility with the Delta and Omicron variants was independent of close contact or location. The prevalence rates of cough, fatigability, and fever were similar in young children infected by the Delta and Omicron variants. CONCLUSIONS: COVID-19 transmission in children aged 0 to 3 years increased by 3 to 4 fold during the Delta outbreak and by 8 to 10 fold during the Omicron outbreak compared with the conventional strain outbreak. The symptoms in young children were not different between the Delta and Omicron variants.

Response to Glucocorticoid Therapy in Patients with Mild to Moderate Coronavirus Disease 2019 at a Japanese Care Facility.

The fifth wave of the coronavirus disease 2019 (COVID-19) pandemic caused by delta variant infection depleted medical resources, and the Japanese government announced glucocorticoid use for outpatients. An appropriate outpatient-glucocorticoid treatment for COVID-19 has not been established; therefore, we created treatment manuals with indications for glucocorticoid administration in a care facility adequately equipped to manage patients with mild to moderate COVID-19. Thirty-eight patients (24 males, 14 females; mean age 40.5 ± 11.8 years) were treated with glucocorticoids from August 1 to October 1, 2021 [COVID-19 staging, mild (n = 1), moderate I (n = 19), and moderate II (n = 18)]. Patients were treated with 6.6 mg/day d.i.v. or 6 mg/day p.o. dexamethasone, or 20-30 mg/day p.o. prednisolone. The median (25th-75th percentile) number of days from the date of onset to glucocorticoid administration was 8.0 days (7.0-11.25 days). While 24 patients were hospitalized, the condition of 14 improved without hospitalization. The median number of days from glucocorticoid administration to hospitalization was 1.0 day (range, 1.0-1.0 day). In the non-hospitalized patients, the median number of days of glucocorticoid administration was 5.0 days (5.0-5.25 days). The mean number of days from glucocorticoid administration to discharge from the care facility for non-hospitalized patients was 8.4 ± 3.3 days. The adverse reactions among non-hospitalized patients included insomnia (n = 1) and mild liver dysfunction (n = 3). The present method of glucocorticoid administration can be safely used for patients with COVID-19 in care facilities.

Variation in the prevalence of cough symptoms 4-5 days after infection with SARS-CoV-2 between seasons with different prevalent strains.

Background: The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains a major global health concern in 2022. The association between the rapid spread of the variants, which eliminated the original strain, and clinical manifestations with the variants remains undetermined. Methods: This was a population-based longitudinal cohort study. Whole citizens in a city with approximately one million population who had contacted COVID-19 patients and were tested by nasopharyngeal SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR) swab test between July 2020 and March 2021 were enrolled. Detailed contact episode and the presence of cough symptoms 4-5 days after contact with patients having COVID-19 were evaluated. Results: Among the 359 RT-PCR test-positive patients, 88 (24.5%) developed cough symptoms by 4-5 days from the infection. The same rate in RT-PCR test-negative cases was 8.6%. The prevalence of cough did not significantly differ by age, sex, and places or closeness of the contact episode. The rate of cough symptoms in RT-PCR test-positive patients increased in February-March 2021 with E484K variant predominance compared to that in July-December 2020 with the original strain (32.9% vs 19.4%, p = 0.0221), whereas the cough prevalence among RT-PCR test-negative population did not increase. Cough symptoms in COVID-19 patients was associated with strong fatigability, but was independent from fever or dysosmia. Conclusions: Cough symptoms 4-5 days after infection with SARS-CoV-2 was suggested to have increased with E484K variant, compared to the original strain.