VTPB - Coronaviruses (SARS, MERS, COVID-19)

SARS-CoV2 - common name

COVID-19 (most well known)

Severe Acute Respiratory syndrome (SARS)(SARS-CoV)

Viral respiratory disease, first identified in Feb/March 2003, outbreak in 2002

Middle East Respiratory Syndrome (MERS)

Viral respiratory disease, first identified in 2012

What are coronaviruses (CoVs)?

• Large family of RNA viruses

• Cause respiratory, gastrointestinal, liver, neurological issues

• In birds & mammals (humans obvi)

Known for high mutation rates & new strains

RNA viruses

SARS CoV - history

• Guangdong province, Southern China —> Hong Kong

• Outbreak in 2002-2003

• Lack of immediate transparency by Chinese Gov.

• Human cases not seen since 2004

SARS-CoV-1 transmission

• Human-human (respiratory droplets)

• Hospital superspreaders

• NOT transmitted ASYMPTOMATICALLY

• indirect surface transmission

SARS severity/fatality

10% higher than that of COVID-19 patients

SARS intermediate host

Palm Civet Cats

SARS natural reservoir

Horseshoe Bat

ProMED (Program for Monitoring Emerging Diseases)

An early warning system for emerging infectious disease, reported novel outbreak of SARS

International Health Regulations

• revised in 2005, put in force in 2007

• criteria in determining event as public health emergency of international concern

MERS-CoV - history

• First outbreak outside Arabian Peninsula, later in South Korea (2015)

• 2,600 laboratory-confirmed cases, and 949 of them fatal

MERS-CoV transmission

• Respiratory secretions (droplets, not aerosol)

• Primarily spread in healthcare settings (not observed in community)

• Emergence may come from dromedary camels

MERS severity/fatality

• ranges from 20-40%

MERS-CoV (maybe) host reservoir

Bats

MERS-CoV intermediate animal host

Infected dromedary camels

MERS in South Korea

• Single travel case from Saudi Arabia

• Largely confined to close contact health care facilities

• Opened eye of public health measures

Why did basic public health control measures work better against SARS compared to SARS-CoV-2?

Asymptomatic transmission is a major factor driving SARS-CoV-2 community transmission

SARS-CoV-2 history

• Atypical pneumonia case in Wuhan, China

SARS-CoV-2 transmission

• Human-human (airborne droplet and aerosol)

• Asymptomatic transmission

• Easier to spread in close proximity, poor ventilation

COVID-19 acute clinical course

Symptoms mild, asymptomatic —> severe respiratory illness/organ failure

Long COVID

• multisystem (affects respiratory, cardiovascular, renal, endocrine, etc.)

• Range of new/ongoing symptoms, can last weeks/months/longer

• Growing public health crisis

SARS-CoV-2 - Early pandemic timeline

• 2019: pnuemonia outbreak in china

• 2020: human-human transmission, travel restrictions, WHO public health emergency, vaccine distribution

Operation Warp Speed (OWS)

• United States’ COVID vaccines were the best tool to reduce incidence of severe disease, hospitalizations, and death

• Required full forse of USG, private sector, PH, EM, and MANY workers

Ws? of SARS-CoV-2 emergence

We do not have direct definitive evidence of where, when, or how SARS2 emerged

SARS-CoV-2 Policy implications/Lessons learned

• Shortcomings: lacked leadership, organizational structures, & communication

• Caused prolonged lockdowns, vaccine mandates

SARS-CoV-2 variants evolution

• Continuously evolved since emergence in 2019

• Early variants A,B,G - VOC of concern in 2020

• Delta variant in 2021 - enhanced transmissibility

• Late Omicron variants sustaining endemic

COVID-19 US vaccines

• Pfizer-BioNTech (mRNA)

• Moderna (mRNA)

• Novavax (subunit protein, adjuvanted)

• Johnson&Johnson (adeno viral vector)