Quote From the Full Study:

“Our study didn’t find any protective effect of vaccination against new COVID 19 infections. Type of vaccine nor number of doses has any effect on new infection. Those who had prior vaccination have 1.2 times more odds of becoming positive with RT PCR when compared to patients who didn’t have vaccination; however, it is not statistically significant(p>0.05). More samples are needed to conclude
further. Out of the 21 patients who had more than 2 doses of vaccines, the data on days between the second dose of vaccination and date of RT PCR positive was available for 16 patients. 7 of them (43.8%) had a breakthrough infection (RT PCR positive after 14 days of vaccination). (Table 3)

Background & objectives: Establishing concrete evidence on effect of vaccination on severity of SARS CoV-2 infections in real world situations is the need of the hour. The aim of this study is to estimate the effectiveness Covid 19 vaccines in preventing the new and severe SARS CoV-2 infections. Methods: We did this retrospective cross-sectional study among the 4765 patients consecutive adult inpatients admitted in the Covid 19 wards of a tertiary care hospital from May 1,2021 to July 7, 2021 during the second wave of Covid 19 pandemic. Information on basic demographic variables, RT PCR status, vaccination status, outcome and clinical severity of illness were obtained from the electronic hospital patient records. Results, and Interpretation & conclusions: Type of vaccine and number of doses of vaccines didnot have any protective effect against new SARS CoV-2 infection. Covid 19 patients vaccinated with at least one dose had 75 % less risk of requiring oxygen (OR 0.25 CI: 0.15 to 0.44) and 60 % less risk of ICU admission (OR 0.4 CI: 0.2 to 0.6) and it was statistically significant. Only 31 % of fully vaccinated Covid 19 positive patients had oxygen requirement (90% less risk) and 15% of the fully vaccinated patients had needed ICU admission (90% less risk). Conclusion: Vaccination didnot protect against SARS Cov-2 infection however significant protection was documented against severe SARS Cov-2 infection. Vaccination coverage should be increased urgently in order to halt the impending wave of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Competing Interest Statement
The authors have declared no competing interest.

Funding Statement
NIL

Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The institutional ethics board of Tirunelveli Medical College which was conducted on 19.07.2021 had approved the study.No ethical issues were raised.

All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.

Yes

Paper in collection COVID-19 SARS-CoV-2 preprints from medRxiv and bioRxiv