CI	Confidence Interval.
CONSISE	Consortium for the Standardization of Influenza Seroepidemiology.
COVID-19	Coronavirus Disease 2019.
FFX	First Few X Cases and Contacts Protocol.
GISRS	Global Influenza Surveillance and Response System
HAHC	Hakeem Abdul Hameed Centenary Hospital.
HCW	Health Care Worker or Health Worker.
HHC	Household Contacts.
HIMSR	Hamdard Institute of Medical Sciences and Research.
HHTI	Household Transmission Investigation.
ICMR	Indian Council of Medical Research.
IPC	Infection Prevention and Control.
IP	Incubation Period.
LMIC	Low- and Middle-income Country
NABL	National Accreditation Board for Testing and Calibration Laboratories
OR	Odds Ratio.
PI	Principal Investigator.
PPE	Personal Protective Equipment.
PRET	Planned Preparedness and Resilience for Emerging Threats.
RSV	Respiratory Syncytial Virus.
RT-PCR	Reverse Transcription Polymerase Chain Reaction.
SAR	Secondary Attack Rate.
SARS-CoV-2	Severe Acute Respiratory Syndrome Coronavirus 2.
SEARO	South-East Asia Regional Office.
SIR	Secondary Infection Rate.
ToR	Terms of Reference.
VE	Vaccine Effectiveness.
WHO	World Health Organization.
WHO HQ	WHO Headquarters