Infection Prevention and Control in the Healthcare Setting — Questions

a. Wash the wound and encourage bleeding, then report and document the exposure to occupational health.

b. The source is HIV and HBsAg negative, so no HIV or HBV prophylaxis is indicated. The HCV antibody shows exposure but not necessarily active infection, so send source HCV RNA to confirm current infectivity.

c. There is no effective post-exposure prophylaxis or vaccine for HCV. Take a baseline HCV serology from the worker, then follow up with HCV RNA at about six weeks and antibody at three to six months, and treat early with direct-acting antivirals if seroconversion occurs.

RSV spreads by contact with respiratory secretions and contaminated surfaces, so contact precautions anchor the answer.

• Contact precautions with gloves and gown on entry, and hand hygiene on leaving.
• Single room or cohorting of RSV cases, with dedicated equipment and minimal transport.
• Exclude symptomatic staff, restrict visitors, and clean the near-patient environment.
• Add droplet precautions for procedures that generate respiratory secretions.

A complete answer names the important nosocomial viruses and their burden, then the layered measures that prevent spread.

• Respiratory viruses, respiratory syncytial virus (RSV) and influenza, spread readily on paediatric and elderly wards.
• Enteric viruses, norovirus and rotavirus, cause explosive ward outbreaks.
• Bloodborne viruses, hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV), follow sharps injuries and unsafe injection.
• Varicella-zoster virus (VZV) and measles threaten nonimmune patients and staff.

Prevention is layered: hand hygiene above all, standard precautions for every patient, transmission-based precautions matched to route, healthcare worker vaccination, exclusion of symptomatic staff, environmental cleaning, and surveillance with prompt outbreak response.

Varicella is airborne, so it needs more than the skin precautions HSV requires.

• Varicella requires both airborne and contact precautions: a negative-pressure isolation room, only immune staff entering, and prophylaxis or vaccination for exposed nonimmune contacts, on a base of hand hygiene and standard precautions.
• HSV is not airborne, so standard precautions suffice, with contact precautions added for neonatal, disseminated or severe mucocutaneous lesions.

Varicella requires both airborne and contact precautions, because the virus spreads in droplet nuclei and by contact with vesicle fluid. Disseminated zoster is handled the same way.

Any single category, or standard precautions alone, leaves one route uncovered.

Norovirus spreads by the faecal-oral route and contaminated surfaces, so contact precautions with gloves and gown are required, alongside soap-and-water hand hygiene. It has a strong propensity for ward outbreaks.

It is not airborne or droplet-spread, and standard precautions alone are insufficient during an outbreak.

Soap and water is preferred after caring for a patient with Clostridioides difficile, because alcohol is poorly active against spores and the mechanical washing helps remove them. The same applies after norovirus, a non-enveloped virus.

Alcohol rub is the routine agent otherwise, but it and the other waterless options do not remove spores.

Nucleic acid amplification testing detects viral genome directly, appearing before antibody, so it shortens the infectious window. It complements, rather than replaces, serology and donor selection.

It neither abolishes all risk nor is limited to one virus, and it can be run on individual donations, not only pools.

An outbreak is a rate of infection significantly above the endemic baseline, which is why surveillance first establishes that baseline rate. Without it, a cluster cannot be judged unusual.

A single case, a fixed time window, an intensive-care location or a shared organism does not by itself define an outbreak.

The reservoir is where the agent persists, which in a hospital is an infected or colonised patient, a healthcare worker, or a contaminated surface or device. Removing or isolating the reservoir is one way to break the chain.

The portals, the transmission route and the susceptible host are the other, separate links in the chain.

Surveillance focuses on device-associated infections, chiefly central-line bloodstream, ventilator-associated and catheter-associated urinary infection, because they carry the greatest preventable burden. Rates are expressed per device-day for fair comparison.

The other options are not the priority targets of healthcare-associated infection surveillance.

The residual risk is the window period: a donation given after infection but before any test can detect it. Nucleic acid testing shortens this window but cannot close it entirely.

Labelling errors, bacterial contamination, plasma reactions and storage lesions are separate transfusion issues, not the viral residual risk.

The weight of evidence now holds that respiratory viruses are shed predominantly in small particles that stay suspended and are inhaled, so a share of transmission once attributed to large droplets is in fact airborne. Droplet-precaution guidance for these viruses is now questioned.

Blood, faeces and skin scales are not the main vehicles for respiratory-virus spread.

Standard precautions apply to every patient, in every setting, at all times, because any patient may be colonised or infected without this being known. They are the baseline on which transmission-based precautions are added.

Restricting them to known-infected, immunocompromised, intensive-care or isolated patients would miss the undiagnosed carrier.

Seasonal influenza is a droplet infection, needing a surgical mask on entry and no special ventilation. It escalates to airborne precautions only during aerosol-generating procedures such as bronchoscopy or intubation.

Newer evidence suggests a real airborne contribution, and this guidance is under review, but droplet precautions remain the standing recommendation outside aerosol-generating procedures.

SARS-CoV-2 is shed before symptoms begin, exposing contacts in the roughly two days before onset, so universal masking as source control interrupted spread that testing of symptomatic patients would miss.

Already-isolated, recovered and vaccinated people are not the reason masking worked, and the virus is not a bloodborne carrier state.

Whole-genome sequencing is now the front-line typing tool, rapid and detailed enough to be folded into routine surveillance and to supersede older fingerprinting methods. It resolves whether isolates share a single source.

Gel electrophoresis, phage typing, serotyping and antibiogram comparison are older, lower-resolution approaches.

A single-dose vial is used once, for one patient, and a needle and syringe serve only one patient, because reuse transmits bloodborne viruses. Blood-glucose meters and insulin pens are likewise never shared.

Reusing syringes, sharing vials or meters, and hand-recapping needles are all unsafe.

Airborne precautions require a fit-tested N95 respirator, which filters fine particles and seals to the face. A surgical mask does not protect against droplet nuclei.

Cloth coverings, surgical masks and face shields alone are inadequate for an airborne agent.

Measles spreads in droplet nuclei that stay suspended, so it needs airborne precautions with a negative-pressure room and an N95 respirator. Nonimmune staff should not enter.

Droplet, contact or standard precautions alone would not contain an airborne agent.

Healthcare workers are screened for immunity to measles, mumps, rubella, varicella and hepatitis B at employment, with hepatitis B vaccination given to the non-immune, plus annual influenza vaccination. A susceptible worker is both at risk and a potential vector.

Yellow fever, rabies, typhoid and cholera vaccines are travel or exposure specific, not routine occupational requirements.

Gloves do not replace hand hygiene: hands are contaminated during glove removal and through unseen perforations. Hand hygiene therefore follows every glove use.

Gloves are single-use, are required for body-fluid contact, and do not themselves increase skin flora.