March 2024 Healthcare Hygiene magazine March 2024 | Page 8

under the microscope

By Priya Dhagat , MS , MLS ( ASCP ) CM , CIC

Norovirus : Facts and Prevention

• Norovirus is the leading cause of viral gastroenteritis in the country , causing

19 to 21 million cases per year , approximately

109,000 hospitalizations , more than

2 million outpatient visits , and more than

450,000 emergency department visits annually , according to the National Foundation for

Infectious Disease .

The common stomach flu , caused by norovirus , is hitting headlines once again due to recent outbreaks across the United States . Norovirus is the leading cause of viral gastroenteritis in the country , causing 19 million to 21 million cases per year , approximately 109,000 hospitalizations , more than 2 million outpatient visits , and more than 450,000 emergency department visits annually , according to the National Foundation for Infectious Disease .

According to the latest CDC data , the average rate of positive norovirus tests is 12.3 % as of February 17 – an increase from 9 percent in mid-January – and with positivity rates highest in the Northeast , at around 16 percent . In Fairhope , Alabama , more than 1,200 students and staff were infected , forcing an electuary school closure . In Madison County , New York , 15 confirmed cases and 55 suspected cases at Colgate University have been reported . Michigan , Connecticut , and Philadelphia are also reporting outbreaks .

While we ’ re all too familiar with this common stomach bug , why is it such as concern ? Let ’ s take a deeper look into what makes norovirus a uniquely perfect pathogen capable of causing widespread outbreaks .

Norovirus has multiple methods of transmission . The virus is transmitted via the fecal – oral route and vomit – oral route through foodborne , waterborne , contact with contaminated environments , and direct contact with an infected individual .

Norovirus is highly contagious due to its low infectious dose being as little as 18 viral particles capable of causing infection coupled with extreme viral shedding . Billions of virus particles can be shed in the stool and vomit of infected individuals which can easily infect others ( 105 – 1011 viral copies per gram of stool ).

Norovirus is a single-stranded non-enveloped RNA virus , meaning it does not rely on an exterior “ envelope ” for protection . This makes it environmentally stable and resistant the common disinfectants and alcohols . Regardless of the percentage of alcohol in common hand sanitizers , alcohol cannot penetrate the protein shell that surrounds the viral RNA , known as the capsid .

Noroviruses are a genetically diverse . They can rapidly evolve , leading to a lack of prolonged cross-protective immunity following infection . There are over 30 genotypes that can infect humans .

Norovirus particles may be infectious for 2 weeks on environmental surfaces and for greater than two months in water .

In the United States , cases of norovirus occur most frequently during late fall , winter , and early spring , likely due to the virus ’ s ability to survive in cooler temperatures .

Infection is rapid , with an incubation period of 24 to 48 hours , followed by vomiting , diarrhea , nausea ,

• Norovirus outbreaks frequently occur in schools , cruise ships , healthcare settings , and disaster relief settings . In the United States , about

of all norovirus outbreaks occur in healthcare settings . In fact , a recent

62 % study reported 13,092 norovirus outbreaks and

416,284 outbreak-associated cases in long-term care facilities between 2009 and 2018 in all 50 states , Washington D . C ., and Puerto Rico .

abdominal cramps , stomach pain , fever , and body aches . Resolution of symptoms can occur after 12 to 72 hours , however , gastroenteritis can be severe and prolonged in specific risk groups , especially infants , children , and immunocompromised individuals . There is no vaccine for norovirus . Treatment consists of supportive care , especially oral or intravenous rehydration .

Norovirus outbreaks frequently occur in schools , cruise ships , healthcare settings , and disaster relief settings . In the United States , about 62 % of all norovirus outbreaks occur in healthcare settings . In fact , a recent study reported 13,092 norovirus outbreaks and 416,284 outbreak-associated cases in long-term care facilities between 2009 and 2018 in all 50 states , Washington D . C ., and Puerto Rico .

Norovirus outbreak management relies on basic principles of infection prevention : hand hygiene , limiting exposure to infectious individuals , and thorough environmental decontamination . In healthcare settings , patients with norovirus gastroenteritis must be placed on Contact Precautions for a minimum of 48 hours after the resolution of symptoms . Healthcare personnel must wear a gown and gloves when caring for patients and use a mask and eye protection if there is an anticipated risk of splashes , particularly among patients who are vomiting . Strict adherence to hand hygiene using soap and water and environmental cleaning and disinfection using appropriate disinfectants is essential .

Click

here to access the Guideline for the Prevention and Control of Norovirus Gastroenteritis Outbreaks in Healthcare Settings .

Priya Dhagat , MS , MLS ( ASCP ) CM , CIC , is an infection preventionist and the associate director of the system-wide Special Pathogens Program within the Department of Emergency Management at New York City Health + Hospitals , overseeing special pathogen preparedness and response efforts across New York City Health + Hospitals frontline healthcare facilities . Additionally , she supports and offers subject matter expertise for infection prevention topics for the National Emerging Special Pathogens Training and Education Center ( NETEC ).

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