Overall round up on influenza with recent updates. Management guidelines follow our national recommendation.

1. z
Introspecting into
Swine Flu:
Current updates
Speaker: Dr ARNAB NANDY
PGT, Dept. of Paediatrics
NBMC&H
Moderator: Dr SANKAR KUMAR DAS
Head of the Dept.
Dept. of Paediatrics
NBMC&H
28/02/2019

2. z
Introduction
 What is SWINE FLU ?
Respiratory disease of pigs caused by type A influenza viruses that cause
outbreaks of influenza in pigs.
 How does it affect human ?
- Swine flu viruses do not normally infect humans.
- Sporadic human infections with influenza viruses that normally infect
swine can occur.
- Swine influenza virus infections in humans, now called “variant virus
infections in humans” (Example - H3N2 variant virus or “H3N2v” virus).
 According to CDC (Centre for Disease Control) report - beginning in
2012, there is a jump in the number of infected cases with influenza
viruses that usually are found in pigs.
World Health Organization. Standardization of terminology of the pandemic A(H1N1) 2009 virus. Wkly Epidemiol Rec 2011;86:480.

3.  Why are human infections with variant viruses of concern ?
- Pigs are susceptible to avian, human and swine influenza viruses.
- It has the potential to get infected with influenza viruses from different
species at the same time.
- It creates the opportunity for the genes of these viruses to mix and create
a new virus – Antigenic shift.
- Influenza vaccines made against human influenza viruses are generally
not expected to protect people from these variant influenza viruses.
- In 2009, when an influenza A (H1N1) virus with swine, avian and human
genes emerged in the spring of 2009 led to pandemic.
- Last Variant virus infection [A(H3N2)v] reported on 6th July,2018 in a child
at an Indian agricultural fair.

4. http://www.cdc.gov/features/animalexhibits/.
• Spread of variant influenza
virus:
- The main way is when an infected pig
(or person) coughs or sneezes, and
droplets containing virus spread through
the air. If these droplets land in the nose
or mouth, or are inhaled by another
person or pig, infection can result.
- There also is evidence that variant flu
viruses can spread by touching
something that has virus on it and then
touching the eyes, nose or mouth.
- A third way to possibly get infected is to
inhale small particles in the air that
contain variant flu virus.

5. z
Influenza Viruses
 Single stranded RNA virus (eight segments)
 Family – Orthomyxoviridae
 Three types –
- Influenza virus A : Pandemic, Epidemic
- Influenza virus B : Epidemic > Pandemic
- Influenzae virus C : Mostly sporadic illness
 Potential hosts: Pigs, Birds, Humans.
 Identification of strain –
example: influenza A/Victoria/361/2011(H3N1)

6. A schematic diagram of influenza virus
 Reason for high frequency of antigenic variability :
- Antigenic drift (Point mutation)
- Antigenic shift (Genetic reassortment)
 Potential antigens in influenza virus:
- Hemagglutinin (HA) protein → 18 types
- Neuraminidase (NA) protein → 10 types

7. Terebuh P, Olsen CW, Wright J, et al. Transmission of influenza A viruses between pigs and people, Iowa, 2002–2004. Influenza Other Respi Viruses 2010;4:387–396.

8. z
Historical aspect and seasonal trend
 Pandemics had taken millions of lives away :
- 1918 [Influenzae A (H1N1)], Spanish flu
- 1957 [Influenza A (H2N2)], Asian flu
- 1968 [Influenza A (H3N2)], Hong Kong flu
- 2009 [Influenza A (H1N1) pdm09]
 Every year, 3-4 influenza virus types or sub-types circulate at
community level with predominance of one amongst them.
 Seasonal outbreak – spring, late autumn, winter.

9. z
Pathophysiology
 Incubation period : 2-3 days
 Course of illness : 1-2 weeks
 Cell mediated immunity and local humoral mediated immunity plays an
important role. (TNF α, INF γ)
 Viral shredding :
- One day before onset of symptoms up to usually seven days after.
- Severity of illness correlates with viral shredding.
 Serum antibodies against HA : Second week of infection.
 Desquamation of respiratory epithelium, loss of ciliary function,
decreased mucous production – Secondary bacterial infection.

10. Schematic representation of respiratory epithelium infection by influenza virus

11. z
Clinical presentation in children
 Sudden and rapid onset of illness
 Viral prodrome : fever, chills, body ache, malaise, irritability,
feeding difficulty.
 Sore throat, non-productive cough, running nose, headache.
 Cervical lymph nodes can be enlarged.
 Coryza, pharyngitis and dry cough less prominent than systemic
symptoms.
 Abdominal pain, vomiting, diarroea.

12.  Red flag signs :
- Somnolence,
- High and persistent fever,
- Difficulty in feeding
- Convulsions,
- Shortness of breath,
- Drowsiness,
- Chest pain,
- Instability of vital signs,
- Worsening of underlying chronic condition (if any).
 Complications :
Secondary bacterial infection, pneumoniae, bronchiolitis, croup, acute otitis
media, severe dehydration, myocarditis, myoglobinuria, encephalitis,
myelitis, Reye's syndrome, toxic shock syndrome, exacerbation of chronic
disease etc.

13. z
Risk population
- Children < 5 years
- Older age > 65 years
- Pregnant women
- Immunocompromised state
- Co-existing chronic illness
- Long-term immunosuppressive treatment
- Extreme obesity (BMI ≥ 40)
- American Indians, Alaska natives
- Adolescents < 19 years of age on long-term aspirin therapy

14. z
Diagnostic modalities
Prompt clinical suspicion considering epidemiological background
is the key which follows laboratory confirmation.
(A) General diagnostic work-up – Complete hemogram,
electrolytes, serum inflammatory markers, chest X-ray etc.
(B) Specific diagnostic work-up –
 Specimen : Nasopharyngeal (NP) swab, Throat swab, Nasal wash, Nasal
aspirate, Bronchial wash, Endotracheal aspirate.
 Transport of specimen : Kept at 4℃ in viral transport media (VTM) and
should reach laboratory with in 24 hours, if it takes longer then needs to be stored at
– 70 ℃. (STM/ NICED, Kolkata)

15.  Laboratory requests :
- Patient particulars
- Name of the sending hospital and the doctor
- Relevant signs and symptoms and Categorisation
- Pregnancy status
- History of exposure to established influenza cases
 Methods :
 Serological tests : Not performed during acute illness.
Methods Time
Rapid influenza diagnostic tests < 30 min
Immunofluorescence (DFA/IFA) < 4hr
RT-PCR 1-6hr
Viral cell culture 3-10 days

16. z
Management guideline
 Categorisation of illness is required to decide management.
 Whenever strongly suspecting that dealing with a case of influenza infection
(Influenza like illness, ILI) – never wait for laboratory confirmation for starting
anti-viral therapy. (Specially during the seasons of influenza outbreak)
 History of exposure, Clinical condition of the child and High risk condition gets
priority in making treatment decision.
 Supportive treatment along with anti-viral treatment has an important role.
CDC. Antiviral agents for the treatment and chemoprophylaxis of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR
2011;60(No. RR-1).

17. Category Criteria Treatment
Category A
Patients with mild fever and
cough/sore throat with or without
other symptoms like diarrhoea,
headache, body ache
- Confinement at home and avoid
mixing-up
- No anti-viral drug
- Re-assess at 24-48 hrs
Category B (i)
Sign and symptoms of category
A but having high fever and
severe sore throat
- Advice admission
- Collection of clinical sample
- Start anti-viral drug
Category B (ii)
Sign and symptoms of category
A PLUS high risk condition*
- Clinical condition determines
need for admission.
- Domiciliary treatment receiver
should avoid mixing-up for 8-10
days
- Start anti-viral drug immediately
after collecting sample
Category C
In addition to above,
breathlessness, chest pain,
drowsiness, bluish discoloration
of nails, worsening of under lying
chronic condition and other red
flag signs
- Advice admission
- Start anti-viral after collecting
sample
- Kept in isolation
- Supportive treatment
- Ventilatory support(if required)
State Protocol for Swine flu (H1N1)), West Bengal, December 2017

18.  Contact with confirmed influenza cases:
Condition Treatment as
Asymptomatic
Regular follow-up, if develops
symptom with in 7 days of exposure
dealt as Category B (ii)
Asymptomatic but high risk population Chemoprophylaxis
Symptomatic Categorise the patient and manage
 Signs and symptoms for hospitalisation :
- High grade fever
- Shortness of breath
- Chest pain
- Dizziness, confusion
- Severe and persistent vomiting
 Early warning signs : Fast breathing, Bluish skin discoloration, Not drinking
enough fluid, Lethargy, Irritability, High fever with rash.

19. Recommended dosage of oseltamivir as per national guideline :
 Treatment doses –
 Commercially available oseltamivir – 12mg/ml oral suspension.
 In 2012, FDA approved use of oseltamivir in as young as two weeks.
 Zanamivir not approved for use in less than 5 Years of age.
Criteria Dosage & Route Duration
< 3 Months 12 mg bd p.o. 5 Days
3 - 6 Months 20 mg bd p.o. 5 Days
> 6 Months 25 mg bd p.o. 5 Days
< 15 Kgs 30 mg bd p.o. 5 Days
15 - 24 Kgs 45 mg bd p.o. 5 Days
24-40 Kgs 60 mg bd p.o. 5 Days
> 40 Kgs 75 mg bd p.o. 5 Days
For Infants
Above infant
age group

20.  Chemoprophylactic doses of oseltamivir –
 Other groups of anti-viral : Adamantanes group, Wide spread resistance.
Based on age Based on
weight
Dosage &
Route
Duration
< 3 Months Not
recommended
3 - 6 Months 20 mg od p.o. 10 Days
6 - 12 Months 25 mg od p.o. 10 Days
1 - 2 Years < 15 Kgs 30 mg od p.o. 10 Days
3 - 5 Years 15 - 24 Kgs 45 mg od p.o. 10 Days
6 – 9 Years 24-40 Kgs 60 mg od p.o. 10 Days
10 – 12 Years > 40 Kgs 75 mg od p.o. 10 Days
For Infants
Above infant
age group

21. z
Prevention better than cure
 Strengthen surveillance system to detect influenza outbreak
 Timely notification and disease preparedness
 Early implementation of infection control precautions to minimize
nosocomial and household spread through – Vaccination,
Personal protective devices (PPE), Standard operating
procedures (bio-medical waste), Chemoprophylaxis, Isolation.
 Public awareness
 Early identification and follow-up of cases and those having high
risk

22. Vaccines :
- Influenza vaccination is the best means of preventing the illness (efficacy → 50-80%)
- Types of vaccines : 1. Inactivated influenza vaccine (IIV), i.m. route
2. Live attenuated influenza vaccine (LAIV), nasal spray, preferred
3. Recombinant hemagglutinin influenza vaccine, egg free, injectable
- LAIV recommended for children of 2 years or more with special precaution between 2-8
years of age
- Good safety profile
- Trivalent or quadrivalent, depending upon availability
- Side effects : Soreness, redness, swelling of the injection site, nasal congestion after
nasal spray
- Frequency of vaccination – yearly (late summer and early fall of each year)
- Vaccine takes 2-3 weeks for development of immunity
- For 2017-18, Indian Council of Medical Research recommended trivalent vaccine
containing : Influenza A/Michigan/45/2015 (H1N1)pmd09 like virus
Influenza A/Hong Kong/4801/2014 (H3N2) like virus
Influenza B/Brisbane/60/2008 like virus
https://www.cdc.gov/flu/about/qa/nasalspray.htm

23. - For the 2018-2019 flu season, the Advisory Committee on Immunization
Practices (ACIP) recommends annual influenza vaccination for everyone 6 months
and older with any licensed age-appropriate flu vaccine including inactivated
influenza vaccine (IIV), recombinant influenza vaccine (RIV4) or live attenuated
influenza vaccine (LAIV4) with no preference expressed for any one vaccine over
another.
- All nasal spray flu vaccines for the 2018-2019 season will contain four flu
viruses: an influenza A (H1N1) virus, an influenza A (H3N2) virus and two influenza
B viruses.
Has the child
ever received
influenza
vaccine?
Yes
Did the child
receive a total of
2 or more doses
of seasonal
influenza
vaccine since
July 1, 2010
Yes
1 Dose
No/Don’t
know
2 Doses
No/Don’t
know
2 Doses
- Different types of influenza
vaccines have different age specific
recommendation which needs to be
checked before their administration.
- Contraindications and condition needs
precaution also need to be checked.
CDC. Antiviral agents for the treatment and chemoprophylaxis of influenza:
recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR
2011;60(No. RR-1).
Influenza vaccine dosing
algorithm for children 6
months to 8 years

24.  Some people should not get the nasal spray flu vaccine (LAIV):
- Children younger than 2 years
- Adults 50 years and older
- Pregnant women
- People with a history of severe allergic reaction to any component of the vaccine or to a previous
dose of any influenza vaccine
- Children 2 years through 17 years of age who are receiving aspirin- or salicylate-containing
medications.
- People with weakened immune systems (immunosuppression)
- Children 2 years through 4 years who have asthma or who have had a history of wheezing in the
past 12 months.
- People who have taken influenza antiviral drugs within the previous 48 hours.
- People who care for severely immunocompromised persons who require a protected environment
(or otherwise avoid contact with those persons for 7 days after getting the nasal spray vaccine).
 In addition, the following conditions are precautions to the use of the nasal spray influenza vaccine
(LAIV):
- Asthma in people aged 5 years and older.
- Other underlying medical conditions that can put people at higher risk of serious flu complications.
- These include conditions such as lung disease, heart disease (except isolated hypertension),
kidney disease (like diabetes), kidney or liver disorders, neurologic/neuromuscular, or metabolic
disorders.
- Moderate or severe acute illness with or without fever.
- Guillain-Barré Syndrome within 6 weeks following a previous dose of influenza vaccine

25. Personal protective devices :
Triple layer surgical mask
- Screening area
- Isolation ward
- Ambulance staff
- Community health
worker
N 95 face respirator mask
- Critical care facility
- Laboratory
 Do-s and Don’t-s need to be strictly adhered to regarding use of masks and other
PPE

26.  Few important facts regarding domiciliary care :
- Laid for category A and some of category B (ii) patients
- Stay at home for seven days in a well ventilated room preferably isolated
- Wear mask all the time (Triple layer surgical mask)
- Family members should also use masks
- Maintain an arm’s length (one meter) at least whenever communicate
with others
- If mask not available use handkerchief
- Discard mask or handkerchief after six hours or if it gets wet
- Proper hand washing and maintenance of hygiene
- Monitoring for worsening of symptoms
 Chemoprophylaxis is not routinely recommended for influenza unless
- Unvaccinated person at high risk of developing influenza complications
- Vaccine is contraindicated or having low-effectiveness
- Exposure to confirmed cases of influenza who considered under high risk
population
- Institutional influenza outbreaks

27. z
Thank you