A recent study by the Indian Council of Medical Research presented that involving a combination of two COVID-19 vaccines elicited better immunogenicity than two doses of the same vaccine. The study was done based on an event in UP, India of mixed dosing which raised anxiety in the public domain, with the potential of vaccine hesitancy.

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Introduction

The study had 18 participants who got two doses of two different vaccinations. Indian Council of Medical Research has discovered that a combination of Covishield and Covaxin, the two primary vaccines used in India's COVID immunisation program, can actually provide superior outcomes. The research enrolled just 18 residents of Uttar Pradesh's Siddharth Nagar, who received two doses of two distinct vaccinations by accident.

According to the study's findings, which have not yet been peer-reviewed, immunisation with a combination of an adenovirus vector platform-based vaccine and an inactivated whole virus vaccine was not only safe but also evoked a higher level of immunogenicity. Covishield is an adenovirus vector platform-based vaccine made by Pune's Serum Institute of India, whereas Covaxin is a complete virus vaccine developed and manufactured by Bharat Biotech and the ICMR. Covishield and Covaxin are two distinct jabs.

The paper, titled 'Serendipitous COVID-19 Vaccine-Mix in Uttar Pradesh, India: Assessment of the Safety and Immunogenicity of a Heterologous Regime,' has been posted to medRxiv. Eighteen persons got two doses of two different vaccinations, and their reactions were compared to those of 40 receivers of two doses of Covishield and 40 recipients of two doses of Covaxin. The research was scheduled to run from May through June 2021, according to the statement.

Internationally, the practice of combining vaccinations is being examined, and all studies support the use of two vaccines to give protection against future diseases. In July, the Central Drugs Standard Control Organisation's subject expert committee recommended that 300 healthy volunteers be enrolled in a trial combining Covishield and Covaxin at the Christian Medical College in Vellore.

While the clinical trial will evaluate the effectiveness of the Covishield and Covaxin combo, the ICMR's study was based on the blunder that occurred in May. The beneficiary misunderstanding had no immediate adverse consequence. Additional study has revealed that the mix-up actually enhances protection since these individuals acquire a higher level of protection than those who got two identical vaccine doses.

What proof exists that combining two distinct vaccinations is beneficial?

Several preliminary trials from the United Kingdom and Spain suggest that both the Oxford-AstraZeneca and Pfizer-BioNTech COVID-19 vaccines induce a robust immune response against the SARS-CoV-2 virus. A trial involving over 600 participants and published online on May 18, 2021, was the first to demonstrate the advantages of mixing various coronavirus vaccinations.

Another research by the University of Oxford, the Office of National Statistics (ONS), and the Department of Health and Social Care (DHSC) indicated that combining vaccinations had favourable medical results. The purpose of this study was to better understand the effect of vaccination on antibody responses and new infections in a large sample of individuals aged 16 years and older. This study discovered that 21 days after receiving a single dose of either the Oxford-AstraZeneca or the Pfizer-BioNTech vaccine (without receiving a second dose), the rates of all new COVID-19 infections decreased by 65%, symptomatic infections decreased by 72%, and infections without reported symptoms decreased by 57%.

This is strong evidence since this study analysed 1,610,562 test results from 373,402 nose and throat swabs obtained between December 1, 2020, and April 3, 2021. Similarly, another study published in medRxiv found that vaccinations appeared to decrease the chance of infection. These researches demonstrated that combining and cocktailing vaccines aids in obtaining optimal immunity in humans and covers the majority of possible issues (VoCs).

What does the WHO have to say about the mixing of COVID vaccines?

In July, WHO Chief Scientist Soumya Swaminathan cautioned against mixing and combining COVID-19 vaccines from various manufacturers, describing the practice as a "dangerous trend" because of the scarcity of evidence. "So it's a potentially dangerous trend here. We're in a data-free, evidence-free zone in terms of mix-and-match. There is limited data on mix-and-match. It will be a chaotic situation in countries if citizens begin deciding when and who will take a second, third, and fourth dose," Soumya Swaminathan said.

The problem of combining vaccinations is delicate, as the World Health Organisation has advised against it. Dr VK Paul, a member of the Niti Aayog's (health) committee, previously stated that combining two vaccinations is theoretically not an issue because the second dosage will function as a booster shot. However, as the government's vaccination push began on January 16, it urged health professionals to exercise extra caution in ensuring that recipients received their second dose of the same vaccine as their first dose.

Implication for India

These promising findings of mixing vaccines have significant implications for the COVID-19 vaccination campaign since heterologous immunisation will open the way for the induction of enhanced and more effective protection against variant SARS-CoV-2 strains, according to the ICMR. These mixed regimens will also assist in overcoming the problems associated with vaccination shortages and removing hesitation about vaccines in people's minds that may have originated as a result of programming 'errors,' particularly in contexts where several COVID-19 vaccines are employed.

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.

The author is a practising super specialist from New Delhi.