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Contents
Source: The post is based on an article “Towards a super vaccine” published in The Times of India on 6th August 2022.
Syllabus: GS 3 science and technology – new developments in the field of biology
Relevance: Biological Disaster; Monkeypox and Covid-Pandemic
News: On July 23, WHO declared monkeypox a Public Health Emergency of International Concern (PHEIC), the highest level of alert. Since Covid in February 2020, this is the second such alert in two years.
Nature of Monkeypox
This international monkeypox outbreak is largely restricted to those below 40 years of age, who were born after the smallpox vaccination ended in 1980.
History of Smallpox Vaccine Development
(1) Ancient Variolation: It was an ancient method practiced in India, China, and the Orient. This involved introducing a tiny amount of pus from the smallpox pustule into the recipient’s arm. It produced immunity. Later on, Lady Mary Wortley Montagu introduced it to 18th-century Britain.
(2) In 1763, John Fewster, a local surgeon in Gloucestershire, discovered cross-protection between cowpox and smallpox. In 1801, Edward Jenner understood the implications of this revolutionary medical advance of cross-protection, and he predicted that this vaccination would rid the world of smallpox.
(3) In the 1930s, the ‘vaccinia viruses’ were used for the development of a smallpox vaccine to eradicate smallpox.
(6) The first-generation smallpox vaccine was made by growing the vaccinia virus in the skin of animals – mostly cows, but also sheep.
(7) The second-generation vaccine used live vaccinia virus grown in eggs or in cell culture, being introduced in the late 1950s and early 1970s, respectively.
(8) A freeze-drying method developed in the early 1950s allowed the vaccine to be stored and transported at room temperature.
(9) Between 1958 and 1977 it was mainly the second-generation vaccine that was used in smallpox eradication programmes.
(10) Third-generation vaccines introduced in the late 1970s are based on a Turkish strain – Modified Vaccinia Ankara (MVA) – which had lost the ability to multiply in humans; it could still be grown well in chicken embryos.
The smallpox-monkeypox vector: Two smallpox vaccines are approved for use against monkeypox.
1) ACAM2000 is a second-generation vaccine that includes live vaccinia virus, which replicates in the recipient and has unpleasant side effects.
2) MVA-BN is a third-generation vaccine, which uses MVA technology developed in the 1990s and has a better safety profile. It is licensed under three brand names – Jynneos (US), Imvanex (EU)and Imvamune (Canada).
In 2019 a clinical study showed equivalence between the MVA and ACAM2000 vaccines, with the former showing better post-vaccination safety.
Several studies have established MVA-based candidates to have good efficacy against monkeypox.
Thereafter, MVA/S was developed. As per a study, MVA/S vaccination produced strong neutralising antibodies and cellular immunity against the Covid virus.
The Way Forward
The monkeypox-Covid vector: There are chances that MVA/S may provide protection against both Covid and monkeypox. Therefore, it can be used to develop a single vaccine that can protect against two diseases that are circulating now and both have been declared as a PHEIC rating.
