CME INDIA Presentation by Dr. Rajeev Jayadevan, MD, DNB, MRCP, ABIM (Med) ABIM (Gastro), NY. Vice Chairman, Kerala state IMA Research Cell. Member, National IMA Task Force on Corona Epidemic, Cochin.

Balancing benefit and risks

Bharat Biotech’s Covaxin has become the world’s first Covid-19 vaccine approved for use in children as young as 2 years. The Subject Expert Committee on Covid-19 has granted emergency use approval to Bharat Biotech’s Covaxin for children in the 2-18 years age group on 12/10/2021. While only a limited number of nations have introduced vaccination of children so far. The scientific validation of the national policy is on fast move. The other side of the coin is worth to ponder…

Note by Author:

• (I have used an interesting example of helmets ⛑ in the end to illustrate the difference. But it helps to read the entire text to understand the concept)

Children are extremely unlikely to develop complications

• As we know, children are extremely unlikely to develop complications, severe disease or death from COVID-19, unlike adults.
• An older adult at 70 years age is 220 times more likely to die than a young adult of 20 with Covid 19.
• Age is the most significant risk factor for COVID complications, and the difference between age groups is exponential, not linear.
•  In Kerala, the Paediatric Covid mortality is only 0.008%, which is very close to zero. Most of these were children with co morbid conditions. In other words, in the case of children, the risk of getting a complication is so much lower than even the youngest adult.

Number required will be far greater

• The number of people required to be vaccinated to prevent one complication will be far greater in the case of children.
• This raises the question of vaccine-related complications and morbidity. The panic created by any bad outcomes in children can in fact be counter-productive for the entire paediatric vaccination process. This may increase hesitancy to other vaccines.

Long COVID is extremely rare in the Kerala

• context, even though a few (not all) European studies seem to suggest a greater incidence. It is possible that their profile or study methodology is different.
• I have personally checked with 25 paediatricians in various types of practice in Kerala who have said that they have not seen an uptick in long Covid patients in spite of several lakhs of children getting infected. Only one doctor saw a slight uptick in cases. Although not a large survey, this gives an overall idea.
• It is important to check with paediatricians with abundant real-life experience, rather than rely on Lancet or NEJM for such matters. This means that for the most part, Long Covid remains a complication of a few.

MIS-C is an uncommon and delayed complication

• that is seen more in tertiary apex centres. It is also treatable when diagnosed early.
• Besides, I do not believe vaccination is going to stop long Covid or MIS-C because breakthrough infections are common after vaccination.
• We know that current COVID vaccines do not provide good mucosal immunity. They do provide systemic immunity which prevents against organ damage. This systemic immunity is mostly helpful for older adults to escape from organ damage.
• Weak mucosal immunity is also the reason why breakthrough infections are common after the initial few months.

The dilemma of Breakthrough infections

• The latest data from Public Health England shows that the rate of breakthrough infections among vaccinated adults is in fact greater than the rate of infections among the unvaccinated. (I must emphasise here that this is rate of infection per 100,000 population, NOT total number of infections)
• In a Texas prison, outbreak reported by CDC, 70% of fully vaccinated people got infected. (A prison is an example of a group of people who share a common facility)

What do these observations imply?

• This means that within a few months, in a class at any school, both vaccinated and unvaccinated children will be more or less equally likely to carry the virus. While this is a risk, we all have to accept, vaccination of adult family members and school staff will help reduce the impact when children go to school.
• It is true that in the first two months or so of vaccination, the child will not contract the virus. But this protection wanes quickly and that explains the above observations. 
• The question is, is vaccination of crores of healthy children worth it just to prevent a few asymptomatic and mild infections for the first few months alone?

Is Paediatric COVID vaccination unattractive?

• The short period of protection makes Paediatric COVID vaccination unattractive – when done for the purpose of preventing infection.
• (The concept of ‘herd immunity’ is not valid any more for COVID-19, as sterilising immunity does not occur and reinfection/breakthrough infections are common)
• In adults, vaccination is mainly done to prevent severe disease and hospitalisation – which itself is extremely rare among children.
• Therefore, it does not make sense to vaccinate enormous numbers of children to prevent one rare complication.

Should we first prioritise children who need vaccines?

• I propose that we first prioritise children who need vaccines the most.
• These will be children with comorbidities, who are more likely to develop complications.
• An additional subgroup will be children who live with people with cancer and immuno suppressed or elderly relatives who are by themselves at higher risk of Covid-19. These children also may be considered for vaccination on a case-by-case basis.

Keep a careful watch for any vaccine related complications

• I propose that we keep a careful watch for any vaccine related complications that arise in the sub-group. Vaccines produce different complications in different age groups – as evidenced by VITT (young women) and myocarditis (males in late teens and young adulthood).
• Besides, very rare complications like myocarditis, GBS and VITT were not picked up during phase 3 trials of the existing vaccines because they were only done in a few thousands of numbers. They were detected only in phase 4 trials, that is when used in millions of people. Likewise, paediatric vaccines have also not been tried in large numbers yet.
• This means that the possibility of a very rare and unique complication cannot be excluded.

A vaccine essentially works like a helmet

• When giving to large numbers of healthy children who are at low risk, the implications are difficult from the emergency use in high-risk adults authorised in late 2020.
• To put this in very simplistic terms, a vaccine essentially works like a helmet in that it protects the individual from head injury should an accident occur. (A helmet does not prevent an accident)

The metaphor to explain

• Regarding vaccine use in different age groups, let me present this metaphor to explain to lay persons.
• Giving vaccines to people over 40 is like asking people riding two wheelers to wear a helmet. In spite of the inconvenience caused by wearing it, this will definitely prevent large numbers of deaths. That’s because the risk of falling is much higher in the case of two wheelers.
• Giving vaccines to young adults is like asking cyclists to wear a helmet. Yes, it is good practice, and universally done in developed nations. We know it will prevent a few deaths from head injury when a large number of cyclists use them. It is worth the inconvenience caused.
• But giving COVID vaccines to healthy children may be compared to asking people walking on the road to wear a helmet – to protect them in case of the very very rare event of slipping and falling in which case they can escape head injury.

यक्ष प्रश्न (The Yaksha Prashna)    

• Will it work? Yes. 
• But is it necessary? No.

Disclaimer: Views expressed are author’s personal analysis. This may not be in tune with policies. This is to stimulate scientific research and in-depth analysis of outbreaks.

CME INDIA Tail Piece

[1] Summary of evidence on vaccine effectiveness against different outcomes Delta (UK)

Estimates of initial vaccine effectiveness in the general population after a 2-dose course. This typically applies for at least the first 3 to 4 months after vaccination. For some outcomes, there may be waning of effectiveness beyond this point. Courtsey Reference-1

[2] Overall population weighted 4-weekly rolling SARS-CoV-2 antibody seroprevalence (% seropositive) in blood donors from the Roche S and Roche N assays

The impact of the vaccination programme is clearly evident from the increases in the proportion of the adult population with antibodies based on Roche S testing. This was evident initially amongst individuals aged 50 years and above who were prioritised for vaccination as part of the phase 1 programme and since week 15 in younger adults and below as part of phase 2 of the vaccination programme. Roche S seropositivity is now >95% across all adult age groups. Courtsey Reference-1

[3] Effectiveness against transmission

• Several studies have provided evidence that vaccines are effective at preventing infection. Uninfected individuals cannot transmit; therefore, the vaccines are also effective at preventing transmission.
• If some of those individuals who become infected despite vaccination are also at a reduced risk of transmitting (for example, because of reduced duration or level of viral shedding).
• A household transmission study in England found that household contacts of cases vaccinated with a single dose had approximately 35 to 50% reduced risk of becoming a confirmed case of COVID-19. (3)
• Data from Scotland has also shown that household contacts of vaccinated healthcare workers are at reduced risk of becoming a case, which is in line with the studies on infection (4)
• Even with high vaccination rates, maintaining multicomponent prevention strategies (e.g., testing and masking for all persons and prompt medical isolation and quarantine for incarcerated persons) remains critical to limiting SARS-CoV-2 transmission in congregate settings where physical distancing is challenging. (5)

References:

1. COVID-19 vaccine surveillance report-week40. Published: 7 October 2021 Publishing reference: GOV-10076 www.ukhsa.gov.uk The UK Health Security Agency.Public Health England. ‘COVID-19: vaccine surveillance strategy 2021’
2. Pritchard E, Matthews PC, Stoesser N, Eyre DW, Gethings O, Vihta K-D and others. ‘Impact of vaccination on SARS-CoV-2 cases in the community: a population-based study using the UK’s COVID-19 Infection Survey.’ medRxiv 2021: 2021.04.22.2125591
3. Harris RJ, Hall JA, Zaidi A, Andrews NJ, Dunbar JK, Dabrera G. ‘Effect of Vaccination on Household Transmission of SARS-CoV-2 in England’ NEJM 2021 17.
4. V Shah AS, Gribben C, Bishop J, Hanlon P, Caldwell D, Wood R and others. ‘Effect of vaccination on transmission of COVID-19: an observational study in healthcare workers and their households.’ medRxiv 2021: 2021.03.11.21253275
5. US Department of Health and Human Services/Centers for Disease Control and Prevention MMWR / September 24, 2021 / Vol. 70 / No. 38

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