tetano
Editor, Senior Moderator
PLoS Med
. 2021 Apr 29;18(4):e1003609.
doi: 10.1371/journal.pmed.1003609. Online ahead of print.
Efficacy of live attenuated and inactivated influenza vaccines among children in rural India: A 2-year, randomized, triple-blind, placebo-controlled trial
Anand Krishnan[SUP] 1 [/SUP], Lalit Dar[SUP] 2 [/SUP], Siddhartha Saha[SUP] 3 [/SUP], Venkatesh Vinayak Narayan[SUP] 3 [/SUP], Rakesh Kumar[SUP] 1 [/SUP], Ramesh Kumar[SUP] 2 [/SUP], Ritvik Amarchand[SUP] 1 [/SUP], Shivram Dhakad[SUP] 2 [/SUP], Reshmi Chokker[SUP] 1 [/SUP], Avinash Choudekar[SUP] 2 [/SUP], Giridara Gopal[SUP] 1 [/SUP], Aashish Choudhary[SUP] 2 [/SUP], Varsha Potdar[SUP] 4 [/SUP], Mandeep Chadha[SUP] 4 [/SUP], Kathryn E Lafond[SUP] 5 [/SUP], Stephen Lindstrom[SUP] 5 [/SUP], Marc-Alain Widdowson[SUP] 5 [/SUP], Seema Jain[SUP] 5 [/SUP]
Affiliations
Abstract
Background: Influenza is a cause of febrile acute respiratory infection (FARI) in India; however, few influenza vaccine trials have been conducted in India. We assessed absolute and relative efficacy of live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV) among children aged 2 to 10 years in rural India through a randomized, triple-blind, placebo-controlled trial conducted over 2 years.
Methods and findings: In June 2015, children were randomly allocated to LAIV, IIV, intranasal placebo, or inactivated polio vaccine (IPV) in a 2:2:1:1 ratio. In June 2016, vaccination was repeated per original allocation. Overall, 3,041 children received LAIV (n = 1,015), IIV (n = 1,010), nasal placebo (n = 507), or IPV (n = 509). Mean age of children was 6.5 years with 20% aged 9 to 10 years. Through weekly home visits, nasal and throat swabs were collected from children with FARI and tested for influenza virus by polymerase chain reaction. The primary outcome was laboratory-confirmed influenza-associated FARI; vaccine efficacy (VE) was calculated using modified intention-to-treat (mITT) analysis by Cox proportional hazards model (PH) for each year. In Year 1, VE was 40.0% (95% confidence interval (CI) 25.2 to 51.9) for LAIV and 59.0% (95% CI 47.8 to 67.9) for IIV compared with controls; relative efficacy of LAIV compared with IIV was -46.2% (95% CI -88.9 to -13.1). In Year 2, VE was 51.9% (95% CI 42.0 to 60.1) for LAIV and 49.9% (95% CI 39.2 to 58.7) for IIV; relative efficacy of LAIV compared with IIV was 4.2% (95% CI -19.9 to 23.5). No serious adverse vaccine-attributable events were reported. Study limitations include differing dosage requirements for children between nasal and injectable vaccines (single dose of LAIV versus 2 doses of IIV) in Year 1 and the fact that immunogenicity studies were not conducted.
Conclusions: In this study, we found that LAIV and IIV vaccines were safe and moderately efficacious against influenza virus infection among Indian children.
Trial registration: Clinical Trials Registry of India CTRI/2015/06/005902.
. 2021 Apr 29;18(4):e1003609.
doi: 10.1371/journal.pmed.1003609. Online ahead of print.
Efficacy of live attenuated and inactivated influenza vaccines among children in rural India: A 2-year, randomized, triple-blind, placebo-controlled trial
Anand Krishnan[SUP] 1 [/SUP], Lalit Dar[SUP] 2 [/SUP], Siddhartha Saha[SUP] 3 [/SUP], Venkatesh Vinayak Narayan[SUP] 3 [/SUP], Rakesh Kumar[SUP] 1 [/SUP], Ramesh Kumar[SUP] 2 [/SUP], Ritvik Amarchand[SUP] 1 [/SUP], Shivram Dhakad[SUP] 2 [/SUP], Reshmi Chokker[SUP] 1 [/SUP], Avinash Choudekar[SUP] 2 [/SUP], Giridara Gopal[SUP] 1 [/SUP], Aashish Choudhary[SUP] 2 [/SUP], Varsha Potdar[SUP] 4 [/SUP], Mandeep Chadha[SUP] 4 [/SUP], Kathryn E Lafond[SUP] 5 [/SUP], Stephen Lindstrom[SUP] 5 [/SUP], Marc-Alain Widdowson[SUP] 5 [/SUP], Seema Jain[SUP] 5 [/SUP]
Affiliations
- PMID: 33914729
- DOI: 10.1371/journal.pmed.1003609
Abstract
Background: Influenza is a cause of febrile acute respiratory infection (FARI) in India; however, few influenza vaccine trials have been conducted in India. We assessed absolute and relative efficacy of live attenuated influenza vaccine (LAIV) and inactivated influenza vaccine (IIV) among children aged 2 to 10 years in rural India through a randomized, triple-blind, placebo-controlled trial conducted over 2 years.
Methods and findings: In June 2015, children were randomly allocated to LAIV, IIV, intranasal placebo, or inactivated polio vaccine (IPV) in a 2:2:1:1 ratio. In June 2016, vaccination was repeated per original allocation. Overall, 3,041 children received LAIV (n = 1,015), IIV (n = 1,010), nasal placebo (n = 507), or IPV (n = 509). Mean age of children was 6.5 years with 20% aged 9 to 10 years. Through weekly home visits, nasal and throat swabs were collected from children with FARI and tested for influenza virus by polymerase chain reaction. The primary outcome was laboratory-confirmed influenza-associated FARI; vaccine efficacy (VE) was calculated using modified intention-to-treat (mITT) analysis by Cox proportional hazards model (PH) for each year. In Year 1, VE was 40.0% (95% confidence interval (CI) 25.2 to 51.9) for LAIV and 59.0% (95% CI 47.8 to 67.9) for IIV compared with controls; relative efficacy of LAIV compared with IIV was -46.2% (95% CI -88.9 to -13.1). In Year 2, VE was 51.9% (95% CI 42.0 to 60.1) for LAIV and 49.9% (95% CI 39.2 to 58.7) for IIV; relative efficacy of LAIV compared with IIV was 4.2% (95% CI -19.9 to 23.5). No serious adverse vaccine-attributable events were reported. Study limitations include differing dosage requirements for children between nasal and injectable vaccines (single dose of LAIV versus 2 doses of IIV) in Year 1 and the fact that immunogenicity studies were not conducted.
Conclusions: In this study, we found that LAIV and IIV vaccines were safe and moderately efficacious against influenza virus infection among Indian children.
Trial registration: Clinical Trials Registry of India CTRI/2015/06/005902.