IEDCR and icddr,b study finds saliva as an alternative specimen for detection of SARS-CoV-2

As the COVID-19 pandemic erupted, World Health Organization (WHO) recommended the use of nasopharyngeal (NPS) or throat swab for detection of SARS CoV-2 etiology of COVID-19.Collection of nasopharyngeal swab causes discomfort to the person due to invasive collection procedure. There are considerable risks to the healthcare worker while collecting these specimens.


Considering all these, an alternative, non-invasive, reliable and self-collected specimen was explored by Institute of Epidemiology, Diseases Control and Research (IEDCR) and icddr,b. The objective of the study was to investigate the suitability of saliva over the nasopharyngeal swab of suspected COVID-19 patients for detection of SARS-CoV-2.


A total of 596 participants including suspected COVID-19 patients and their contacts were chosen. Both nasopharyngeal swab and saliva were collected from each of these participants at the Coronavirus Facility of Dhaka Hospital, icddr,b. The virology laboratories of IEDCR and icddr,b were involved in detection of SARS-CoV-2 using RT-PCR.


Fever, altered smell and loss of appetite were significantly observed as COVID-19 symptoms among the studied participants. Data was analysed to determe the positivity of nasopharyngeal swab and saliva, and detection of viral load in these specimens. Considering the RT-PCR results as a reference standard, it was found that the sensitivity of saliva specimen is 80.35% which meets the WHO criteria. However, the viral load was higher among the nasopharyngeal swab compared to saliva samples.  


Moreover, the study found:

  • Saliva is an easy-to-get, convenient and low-cost specimen to diagnose COVID-19 compared to nasopharyngeal swab.
  • Saliva yields better results if it is collected within the first five days of the onset of the symptoms.
  • Saliva samples can be collected from home safely – there is no need to travel to sample collection points. Self-collected saliva can reduce the cost of sample collection kit as well as minimize sample collection related risk of infection.




IEDCR conducted this study jointly with USAID’s Alliance for Combating TB in Bangladesh Activity, funded by the United States Agency for International Development (USAID) and implemented by icddr,b from July 2020 to January 2021.


Other studies conducted in different countries also found similar sensitivity. U.S. Food and Drug Administration has approved this testing method (SalivaDirect) based on analyzing saliva samples. France and Singapore's Health Sciences Authority have approved the method too while many other countries are also evaluating saliva testing as an option for diagnosing COVID-19.


The study result dissemination event was organized at the IEDCR on 16 March 2021. Professor Dr Abul Bashar Mohammad Khurshid Alam, Director General (Health), Directorate General of Health Services (DGHS), Ministry of Health and Family Welfare (MoHFW); Professor Dr Nasima Sultana, Additional Director General (Administration), DGHS; ProfessorDr Meerjady Sabrina Flora, Additional Director General (Planning and Development), DGHS; Professor Dr Md. Nazmul Islam, Line Director (CDC), DGHS; Professor Dr Tahmina Shirin, Director, IEDCR, DGHS; Dr Md. Abul Kalam, Global Health Security Specialist, USAID/Bangladesh; representatives from icddr,b were present in the event.





For more info, please contact:


Professor Dr Tahmina Shirin



Phone: 029898796


Dr Mohammad Khaja Mafij Uddin

Assistant Scientist, Emerging Infections, Infectious Diseases Division


Mobile: +88 01755700184