Indan Journal of Medical Research Indan Journal of Medical Research Indan Journal of Medical Research Indan Journal of Medical Research
  Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login  
  Home Print this page Email this page Small font sizeDefault font sizeIncrease font size Users Online: 1884       

   Table of Contents      
CORRESPONDENCE
Year : 2015  |  Volume : 141  |  Issue : 1  |  Page : 125-126

Authors' response


Regional Medical Research Centre (ICMR), Port Blair 744 101, Andaman & Nicobar Islands, India

Date of Web Publication2-Apr-2015

Correspondence Address:
A P Sugunan
Regional Medical Research Centre (ICMR), Port Blair 744 101, Andaman & Nicobar Islands
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0971-5916.154518

Rights and Permissions

How to cite this article:
Sugunan A P, Bhattacharya H, Bhattacharya D, Mandal A, Ghosal S R, Rao R C, Mandal A K. Authors' response. Indian J Med Res 2015;141:125-6

How to cite this URL:
Sugunan A P, Bhattacharya H, Bhattacharya D, Mandal A, Ghosal S R, Rao R C, Mandal A K. Authors' response. Indian J Med Res [serial online] 2015 [cited 2019 Jul 16];141:125-6. Available from: http://www.ijmr.org.in/text.asp?2015/141/1/125/154518

Sir,

We thank Dr. Gozdas for his valuable comments on our article [1] . The article describes the results of a follow up screening of a subsample of a cohort that participated in an earlier study of immunological response to an indigenous hepatitis B vaccine [2] . The original cohort was from the Nicobarese community of Car Nicobar Island and consisted of individuals who were negative for both HBsAg and anti-HBsAg irrespective of their anti-HBc status.

We agree that ideally the subjects should have been screened for anti-HBc antibodies and those negative only should have been selected into the study. But, the purpose of the original study [2] was to assess the effect of a vaccination programme in terms of the trend in seroprotection among vaccinated subjects. In view of resource constraints, it might not be practical in a programme to screen all the subjects for HBsAg, anti-HBsAg antibody and anti-HBc to determine eligibility for vaccination. Murhekar et al [2],[3] described the immunological response of the cohort till the end of three years and these articles had presented seroprotection rates by pre-vaccination anti-HBc status. Anti-HBc positive individuals had anamnestic response only after the first dose of vaccine. The proportion of seropositives and geometric mean titre (GMT) after the second and third doses of vaccine and at the end of second and third years after vaccination were comparable in both the groups.

The trend in seroprotection was assessed during the first three years by Murhekar et al[2],[3] and by us now by conducting cross-sectional surveys of subsamples of the vaccinated cohort. There could be a probability that various characteristics including the proportions of isolated anti-HBc positives among the subsamples were different due to sampling error. This is a limitation of non-stratified sampling. Non-stratified sampling is done with the assumption that when the sample size is fairly large, the probability of the sample being drastically different from the population in terms of various characteristics is small. Initial anti-HBc status cannot be termed as a confounder because a confounder needs to influence both the exposure and the outcome. Anti-HBc status may influence anti-HBsAg response, but not selection into the vaccination cohort.

The screening of the subjects during the initial phase was one month after each dose of vaccination [2] . The labelling of the third point of the X-axis of the Figure should have been '7 months' instead of '6 months [1] '.

 
   References Top

1.
Sugunan AP, Bhattacharya H, Bhattacharya D, Mandal A, Ghosal SR, Rao RC, et al. Impact of hepatitis B immunization among the Nicobarese tribe-antibody titres & seroprotection five years after vaccination. Indian J Med Res 2014; 139 : 427-30.  Back to cited text no. 1
    
2.
Murhekar MV, Murhekar KM, Arankalle VA, Sehgal SC. Immune response to an indigenously developed hepatitis-B (Shanvac-B) vaccine in a tribal community of India. Vaccine 2002; 20 : 3431-5.  Back to cited text no. 2
    
3.
Murhekar MV, Murhekar KM, Sehgal SC. Hepatitis B vaccination in a hyper endemic tribal community from India: assessment after three years. Vaccine 2004; 23 : 399-403.  Back to cited text no. 3
    




 

Top
 
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
    References

 Article Access Statistics
    Viewed361    
    Printed9    
    Emailed0    
    PDF Downloaded126    
    Comments [Add]    

Recommend this journal