Vaccines and immunisation

Coalition for Epidemic Preparedness Innovations

Prelims and Mains

The Coalition for Epidemic Preparedness Innovations (CEPI), launched in 2017, funds vaccines against emerging epidemic threats so that candidates are ready before an outbreak.

A vaccine whose development begins when an outbreak does arrives too late to stop it, so the coalition pays for candidates in advance.
India is a founding member of it.
The Ind-CEPI Mission is India's arm of that effort, run by the Translational Health Science and Technology Institute (BRIC-THSTI) and the Biotechnology Industry Research Assistance Council (BIRAC).
It delivered GEMCOVAC-19, India's first mRNA vaccine against COVID-19.
Covishield, by contrast, is a viral vector vaccine and not an mRNA one.

What changed

13 Sep 2026
- The Minister restated India's position as the world's largest vaccine producer by volume, supplying more than 100 countries.
PIB, 13 Sep 2026: India world's largest Vaccine producer and global supplier by volume: Union Minister Dr Jitendra Singh (opens in a new tab)

UPSC has asked

Prelims 2022: COVID-19 vaccine platforms, including Covishield

National HPV Vaccination Campaign

Prelims and Mains

Cervical cancer is one of the few cancers with a single known cause, and human papillomavirus (HPV) is it.

HPV types 16 and 18 cause most cervical cancers.
The campaign was launched in February 2026 and offers girls of 14 a single free and voluntary dose at government health facilities.
The World Health Organization (WHO) accepted in 2022 that one dose protects girls of this age about as well as two.

What changed

20 Jun 2026BriefA Lancet study found no cervical cancer deaths among women aged 20 to 24 in England after HPV vaccination at 12 to 13. A review at one Indian hospital finds HPV, mainly type 16, increasingly behind oropharyngeal cancers in young patients without tobacco use. Mains: prevention must widen from tobacco control to HPV awareness, vaccination of boys and early screening. The Hindu, 20 Jun 2026: Tobacco apart, HPV is now emerging as a major risk factor for head and neck cancers in young Indians (opens in a new tab) · The Hindu, 19 Jun 2026: Cervical cancer deaths for vaccinated young women fall to zero in England: study (opens in a new tab)

Pneumococcal vaccines

Prelims and Mains

Pneumococcal vaccines protect against Streptococcus pneumoniae, the bacterium that causes pneumonia, meningitis and sepsis when immunity weakens.

It wears a sugary coat, the capsular polysaccharide, that differs from one serotype to the next.
Every vaccine in use aims at that coat, so it protects only against the serotypes it includes.
The ones left out, many of them carrying antibiotic resistance genes, then fill the space, which is serotype replacement.

Plain polysaccharide

Example: Pneumovax 23
Works poorly in infants
Short lived protection

Pneumococcal conjugate vaccines (PCV)

Polysaccharide linked to a carrier protein
Stronger, longer response
The number in PCV13 gives the serotypes covered

From The Hindu, 3 September 2026

What changed

3 Sep 2026
- British scientists reported ZPY-CpG-Ch, a protein based candidate found by reverse vaccinology that carries three surface proteins shared across serotypes and so does not depend on the capsule.
- 80 to 100 per cent of mice survived lethal serotype 1, but only four serotypes were tested and it did not clear bacteria from the upper airways.
The Hindu, 3 Sep 2026: A first step towards a universal vaccine against pneumonia, meningitis (opens in a new tab)

UPSC has asked

Prelims 2020: why Pneumococcal Conjugate Vaccines matter in India

Dengue vaccines: Qdenga, DengiAll and antibody dependent enhancement

Prelims and Mains

LeadIndia's first dengue vaccineJuly 2026

Why in news

The Central Drugs Standard Control Organisation granted marketing authorisation to Qdenga in July 2026, the first dengue vaccine approved in India, for people aged 4 to 60.

Background

Dengue is a viral disease spread by the Aedes aegypti mosquito, which bites by day and breeds in clean standing water.
The virus has four serotypes, DENV-1 to DENV-4. Infection with one gives lasting protection against that one, and only brief protection against the others.

A second infection by a different serotype is often more severe than the first.
India carries close to a third of the world's dengue burden.

Why dengue vaccines are hard to make

Antibodies from a first infection can help a different serotype enter cells in a second infection. This is antibody dependent enhancement.

So a vaccine must protect against all four serotypes equally. Partial protection can leave a person worse off than no vaccine.
An earlier vaccine could be given safely only to people who had already had dengue, which meant testing before vaccination.

The vaccine

Qdenga is a live attenuated tetravalent vaccine, built on a dengue type 2 backbone.

It is given as two doses, three months apart, and needs no test for earlier infection.
In trials it was about 80 per cent effective against confirmed dengue and about 90 per cent against hospitalisation.
The caveat: in people who have never had dengue, protection is shown only against DENV-1 and DENV-2, which raises a concern about later disease from DENV-3.
It is not part of the Universal Immunisation Programme.

All four serotypes, together

A national study found all four serotypes circulating together in eight States and Union Territories, a state called hyperendemicity.

DENV-2 was the most common.
About 7 per cent of patients carried two or more serotypes at once, and were more likely to develop severe dengue.
Which serotype circulates decides how well the vaccine works, so surveillance has to continue alongside it.

The way forward

Keep serotype surveillance running, and watch vaccinated children for later severe disease.
Decide on a public programme only with Indian data on safety in those never infected.
Continue mosquito control, since no vaccine removes the need for it.
Support the indigenous vaccine candidates now in trials.

Prelims facts

Dengue has four serotypes; the vector is Aedes aegypti.
Qdenga: live attenuated, tetravalent, two doses, ages 4 to 60, no test before vaccination.
It is built on a DENV-2 backbone.
Approval in India comes from the Central Drugs Standard Control Organisation.

Open the lead on its own page

Dengue has four serotypes, and antibodies from a first infection can help a different serotype enter cells in a second, which is antibody dependent enhancement and is why dengue vaccines are hard to design: vaccination raises type specific antibodies, which block one serotype, and cross reactive antibodies, which block all four only at high levels and can enhance a new infection into severe dengue once they wane. Qdenga (TAK-003), made by Takeda, is a live attenuated tetravalent vaccine on a dengue type 2 backbone, given as two doses three months apart to people aged 4 to 60 with no test for earlier infection; in July 2026 it became the first dengue vaccine approved in India, outside the Universal Immunisation Programme. DengiAll, by Panacea Biotec with the Indian Council of Medical Research (ICMR), is a physical mix of four weakened serotypes derived from US National Institutes of Health candidates, closely similar to Brazil's Butantan DV, and completed phase 3 enrolment of 10,335 volunteers in January 2026 with two years of follow up before approval.

Antibody dependent enhancement

Vaccination
The vaccine raises type specific and cross reactive antibodies
Cross reactive antibodies
They block all four serotypes only while their levels are high
Levels wane
Over time the cross reactive antibodies fall to low levels
New infection enhanced
Low levels help a new dengue infection instead of blocking it
Severe dengue
The enhanced infection can turn into severe dengue

A vaccine that leaves only waning cross reactive antibodies can make a later dengue infection worse rather than milder.Source: The Hindu, 15 June 2026

What changed

21 Jul 2026LeadIndia's first dengue vaccine