T Jacob John

T Jacob John

orcid

Research Focus & Metrics

Academic Career Length

25Years (2002-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 April 2010 in Vaccine
Verified
Journal Article
Open access
TJT Jacob John
T Jacob John
The National Technical Advisory Group on Immunisation in India (NTAGI) fulfils a need for informing decision-making concerning the introduction of new vaccines and strengthening the Universal Immunisation Programme (UIP). The role and membership of NTAGI have expanded over the years in tune with the emerging needs and priorities of the Government of India. Current challenges include institutionalizing mechanisms to follow-up and monitor recommendations, to support research needs to fill information gaps, and to provide technical assistance for monitoring and periodically reviewing the UIP.

20 November 2022 in Vaccines
Verified
Journal Article
Open access
PDF file
TJT Jacob John
T Jacob John
DDDhanya Dharmapalan
Dhanya Dharmapalan
Genetic variants of vaccine poliovirus type 2, imported from an unknown source, were detected in waste waters in Jerusalem, London and New York in early 2022. Wild poliovirus type 2 was globally eradicated in 1999, but vaccine virus type 2 continued for 16 more years; routine use of the vaccine was discontinued in 2016 and reintroduced occasionally on purpose. As an unintended consequence, type 2 vaccine virus variants (circulating vaccine-derived polioviruses, cVDPVs) that mimic wild viruses’ contagiousness and neurovirulence, have been emerging and spreading. To illustrate, in just the past four years (2018–2021), 2296 children developed cVDPV polio in 35 low-income countries. Many assume that virus transmission is via the faecal–oral route. Sustained virus transmission was documented in London and New York, in spite of high standards of sanitation and hygiene. Here, virus transmission cannot be attributed to faecal contamination of food or drinking water (for faecal–oral transmission). Hence, contagious transmission can only be explained by inhalation of droplets/aerosol containing virus shed in pharyngeal fluids (respiratory transmission), as was the classical teaching of polio epidemiology. If transmission efficiency of VDPV is via the respiratory route where hygiene is good, it stands to reason that it is the same case in countries with poor hygiene, since poor hygiene cannot be a barrier against respiratory transmission. By extrapolation, the extreme transmission efficiency of wild polioviruses must also have been due to their ability to exploit respiratory route transmission. These lessons have implications for global polio eradication. It was as a result of assuming faecal–oral transmission that eradication was attempted with live attenuated oral polio vaccine (OPV), ignoring its safety problems and very low efficacy in low-income countries. Inactivated poliovirus vaccine (IPV) is completely safe and highly efficacious in protecting children against polio, with just three routine doses. Protecting all children from polio must be the interim goal of eradication, until poliovirus circulation dies out under sustained immunisation pressure. OPV should be discontinued under cover of immunity induced by IPV to stop the emergence of new lineages of VDPVs, not only type 2, but also types 1 and 3, to expedite the completion of polio eradication.

1 January 2010 in Indian Pediatrics
Verified
Journal Article
Closed access
PDF file
TJT Jacob John
T Jacob John
MMMahesh Moorthy
Mahesh Moorthy

1 February 2012 in Indian Pediatrics
Verified
Journal Article
Open access
PDF file
TJT Jacob John
T Jacob John
VVVipin M. Vashishtha
Vipin M. Vashishtha

1 November 2011 in Vaccine
Verified
Journal Article
Closed access
TJT Jacob John
T Jacob John
SPS.A. Plotkin
S.A. Plotkin
WOW.A. Orenstein
W.A. Orenstein

18 May 2016 in Indian Pediatrics
Verified
Journal Article
Closed access
PDF file
TJT Jacob John
T Jacob John
MDMukul Das
Mukul Das
VVVipin M. Vashishtha
Vipin M. Vashishtha