Temporal profile of SARS-CoV-2 viral load in posterior nasopharyngeal samples: Analysis of 944 patients in Apulia, Italy

Moris Sangineto, Fabio Arena, Rosella De Nittis, Rosanna Villani, Crescenzio Gallo, Gaetano Serviddio

Research output: Contribution to journalArticlepeer-review


Objectives: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has heavily impacted Italy. The government's restriction measures have attenuated the burden on hospitals. The association of high viral replication with disease severity suggests the potential for lower viral load in milder clinical presentations. Methods: The reverse-transcription-polymerase-chain-reaction (RT-PCR) profile of 944 consecutive, non-replicate, positive retropharyngeal swabs was collected from 3 March to 8 June 2020 to investigate the temporal profile of SARS-CoV-2 viral load in the region of Capitanata, Apulia. Cycle threshold (Ct) values of 3 targets (N [nucleocapsid protein], E [envelope protein] and RdRP [RNA-dependent RNA-polymerase]) were analysed. Results: The median Ct values of the 3 targets increased considerably over the study period, showing a progressive and constant weekly change. The negative detection rate of E and RdRP increased over time. These data suggest that SARS-CoV-2 viral load progressively decreased along the outbreak course. During the first epidemic peak (March and April) the viral load among patients >80-years was significantly higher than for younger subjects. However, in May this age-dependent difference disappeared, underlying viral load reduction in the elderly. Conclusions: An attenuation of viral transmission or pathogenicity during the epidemic course is suggested, likely due to restriction measures, although viral factors might also be considered.

Original languageEnglish
Pages (from-to)696-700
Number of pages5
JournalInternational Journal of Infectious Diseases
Publication statusPublished - Mar 2021


  • Coronavirus
  • COVID-19
  • Pandemic
  • Region
  • RT-PCR
  • SARS-CoV-2
  • Viral load

ASJC Scopus subject areas

  • Microbiology (medical)
  • Infectious Diseases


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