Poliovirus

Question 1

True or false: poliovirus is nationally notifiable?

Answer 1

Yes - urgent.

Question 2

Which organism causes poliovirus?

Answer 2

Poliovirus (an enterovirus)

Types 1, 2, 3

Question 3

How is poliovirus transmitted?

Answer 3

Person-person:
* Droplet
* Faecal-oral

Question 4

What are the clinical features of poliovirus?

Answer 4

95% asymptomatic

• Abortive: URTI/GI/ILI
• Non-paralytic: as above + meningeal irritation
• Paralytic: < 1% of cases; acute flaccid paralysis (1 muscle group to quadriplegia)

Abortive = mild. CFR 5-10%.

Question 5

True or false: vaccine-associated paralytic poliovirus (VAPP) is common?

Answer 5

False.
Very rare complication of OPV.

Question 6

What is vaccine-associated paralytic poliovirus?

Answer 6

Circulating vaccine-derived poliovirus infection (cVDPV) occurs when weakened OPV strain circulates in under-immunised populations, or replicates in an immunodeficient individual, and reverts to a form that causes illness and paralysis.

Question 7

Which groups are high-risk for poliovirus?

Answer 7

• Unvaccinated
• Children < 5yo
• Refugees living in camps
• HCWs / lab workers
• Travellers to endemic areas

Question 8

What are the case definitions for poliovirus?

Answer 8

Paralytic infection
Confirmed: clinical + lab definitive
Probable: clinical only

Non-paralytic infection
Confirmed: lab definitive only without typical clinical features

Case definitions for paralytic for wild, VAPP, cVDPV

Question 9

How is poliovirus diagnosed?

Answer 9

• Viral culture (faeces/blood/CNS/throat)
• PCR
• Acute and convalescent sera

National Enterovirus Refence Lab (VIDRL) differentiates wild type, VAPP, VDP

Question 10

What is the incubation period for poliovirus?

Answer 10

Usually 7-14 days

Range 3-35 days

Question 11

What is the infectious period for poliovirus?

Answer 11

As long as virus excreted

• 1 week from pharynx
• 6 weeks in faeces (inc OPV)

Highest 7-10 days before and after Sx onset

Question 12

How is surveillance for poliovirus conducted?

Answer 12

Stool samples from all children with AFP regardless of provisional diagnosis.

AFP = acute flaccid paralysis

Question 13

What is the outbreak definition of poliovirus?

Answer 13

Single case (either wild / VDPV) considered a public health emergency.

Question 14

How are outbreaks of poliovirus managed?

Answer 14

Usual OB management principles: case, contact, environmental management

See Australia’s poliovirus infection outbreak response plan.

Question 15

How is poliovirus prevented?

Answer 15

• Vaccination - NIPS 2, 4, 6mo and 4 years
• Sanitation and hygiene.

Oovercrowing, poor hygiene and sanitation correlated with infection risk

Question 16

What is the main difference between the OPV and IPV?

Answer 16

OPV is live-attenuated.
IPV is inactivated.

Question 17

Why do high-income countries use IPV over OPV?

Answer 17

No risk of VAPP/cVDPV

Question 18

Why is the oral poliovirus vaccine (OPV) used in developing countries over the inactivated poliovirus vaccine (IPV)

Answer 18

Greater intestinal immunity, low cost, east of administration.

OPV needs to cease for eradication - replaced with IPV.

Question 19

Apart from children (NIP) who is the poliovirus vaccine recommended for?

Answer 19

Unvaccinated people
HCW who have contact with polio
Travellers to endemic countries

Booster every 10 years for HCW and travellers.

Question 20

What resources are available for public health management of poliovirus?

Answer 20

DH protocol.
Australian poliovirus infection outbreak response plan.

No SoNG.

Question 21

How are cases of poliovirus managed?

Answer 21

• Interview - DRSVECT
• Treatment - supportive only; droplet/contact precautions
• Isolation/exlusion - home/hospital until 2 x negative stool samples 7 days apart; no work/school/institution at least 14 days from onset and fully recovered
• Education

DRSVECTA = demo, rfs, sx, vax, exposure, contacts, travel hx, animal contact.

Question 22

Who are considered contacts of poliovirus cases?

Answer 22

• HH
• Shared toilet (workplace, school, CC)
• HCW who cared for case
• Lab worker
• Ate food prepared by case

Question 23

How are contacts of poliovirus managed?

Answer 23

• Treatment - check immunisation status; IPV booster (or full course) for all contacts
• Isolation/exclusion
  HH contacts quarantine at home until 2x negative stool samples 24-48hrs apart.
  Consider excluding contacts from high-risk occupations (food handler, HCW, CC) until known not infectious
• Monitor -
• Education - Sx, transmission, resp/hand hygiene

Question 24

What environmental management is required for poliovirus?

Answer 24

Effective disinfectants are those which contain free chlorine, such as sodium
hypochlorite or bleach, glutaraldehyde solutions, formaldehyde solutions and
iodophores.

Question 25

How many WHO regions (including Australia) are polio free?

Answer 25

5 out of 6

Question 26

When was the Global Polio Eradication Initiative (GPEI) launched?

Answer 26

1988

Question 27

Which countries have wild type polio circulating?

Answer 27

Afghanistan and Pakistan

Question 28

How many global cases of polio were there in 2023?

Answer 28

536

Question 29

True or False: poliovirus is considered a PHEIC?

Answer 29

True