Delta major reason for Covid breakthrough infection: 10 findings of ICMR study

From the breakthrough infection samples that ICMR studied, it found that Alpha was predominant in north India, while Delta and Kappa caused 2nd-time infections in the rest parts of the country.

The Indian Council of Medical Research conducted a nationwide study on breakthrough Covid infection when an individual gets infected even after vaccination -- either one dose or both doses. Reinfections and breakthrough infections are not uncommon; as several such cases have been reported during the second wave of the pandemic. While natural immunity which develops after getting the infection once is likely to protect for 10 to 11 months, studies are on to find out how long vaccine-induced immunity stays.

The ICMR study also noted that between March and June, there was "high community transmission" of the Delta variant, followed by Alpha and Kappa variants. (PTI)

For this study, ICMR collected 677 clinical samples of individuals who have been partially or fully vaccinated but have again contracted the infection.

Here are the top 10 findings:

1. Majority (Over 86 per cent)of the breakthrough infections have been caused by the Delta variant.

2. Only 9.8 per cent of such cases (breakthrough) required hospitalisation.

3. Fataity was observed in only 0.4 per cent of cases.

4. The study found that Alpha was predominant behind reinfection in the northern region.

5. Delta and Kappa mainly caused breakthrough infections in the southern, western, eastern and north-western regions.

6. Around 71% of these breakthrough infections were symptomatic and 29% was asymptomatic. The symptoms included fever, nausea, cough, sore throat etc. A smaller proportion reported a loss of smell and taste. Only 6 per cent reported breathlessness.

7. Vaccine has effectively reduced Covid-19 severity and the number of hospitalisation, the study confirmed.

8. Vaccine alone, however, may not be a protection against contracting the infection as out of the 677 patients whose samples were studied, 85 got infected after taking the first dose. The rest 592 received both the doses and then got infected.

9. Though this is not a study on the effect of the vaccines, it has been noted that among these 677, 604 received Covishield, 71 Covaxin and two received China's Sinopharm vaccine.

10. The study also noted that between March and June, there was "high community transmission" of the Delta variant of the infection, followed by Alpha and Kappa variants.

The samples were collected from 17 states and Union territories, including Maharashtra, Kerala, Gujarat, Uttarakhand, Karnataka, Manipur, Assam, Jammu and Kashmir, Chandigarh, Rajasthan, Madhya Pradesh, Punjab, Puducherry, New Delhi, West Bengal, Tamil Nadu and Jharkhand.