Association between Covishield vaccine and menstrual disturbance. Findings from a cross-sectional study among participants of Zero TB cohort in India.

BACKGROUND: The association between covid-19 vaccine and menstrual disturbance is unclear. METHODS: An in-person cross-sectional survey among female members ≥ 18 years enrolled in an ongoing Zero TB prospective cohort in Northern India who had received one or two doses of covid-19 vaccine was conducted to study the characteristics and association of menstrual disturbance within six months of receiving Covishield. RESULTS: Between June 29 and September 5, 2021, 339 females ≥ 18 years of age were administered the survey. Median age was 30 (IQR: 22-39) years; 84 % were between 18 and 49 and 16 % were ≥ 50 years old. There were 152 college students, 27 healthcare workers, and 160 nuns. Forty-two women (12 %) had received one dose and 297 (88 %) had received two doses of Covishield. Overall, 66 (20 %) women reported experiencing menstrual disturbance after receiving Covishield vaccine. The problems included early menstruation: 6 % (n = 19/339); late menstruation: 4 % (n = 14/339); and heavier bleeding: 5 % (n = 17/339). Disturbances lasted for less than seven days and cycles normalized in 1-3 months. There was no post-menopausal bleeding. There was no significant difference in menstrual disturbance based on receiving one vs. two doses of Covishield (OR: 1.58; 95 % CI: 0.55-4.57; p = 0.381). History of SARS-CoV-2 infection was not associated with the development of menstrual disturbance among the vaccinees (OR: 0.63; 95 % CI: 0.24-1.73; p = 0.379). Presence of emotional disturbance at baseline (OR: 31; 95 % CI: 3.52-267; p = 0.002) or previous history of dysmenorrhea (OR: 41; 95 % CI: 8.7-196; p < 0.001) was associated with menstrual disturbance in the vaccinees, indicating their potential to confound or bias study results. CONCLUSION: Menstrual problems were reported by Covishield vaccinees, but they were minor and reversible within three months and do not constitute a ground for vaccine hesitancy. Studies designed to assess causal link taking care to avoid selection bias or confounding are needed.

First and second doses of Covishield vaccine provided high level of protection against SARS-CoV-2 infection in highly transmissible settings: results from a prospective cohort of participants residing in congregate facilities in India.

OBJECTIVES: This study aimed to determine the effectiveness of Covishield vaccine among residents of congregate residential facilities. DESIGN: A prospective cohort study in congregate residential facilities. SETTING: Dharamshala, Himachal Pradesh, India, from December 2020 to July 2021. PARTICIPANTS: Residents of all ages in seven facilities-three monasteries, two old age homes and two learning centres-were enrolled. EXPOSURES: First and second doses of Covishield vaccine against SARS-CoV-2 infection. MAIN OUTCOMES MEASURES: Primary outcome was development of COVID-19. Secondary outcome was unfavourable outcomes, defined as a composite of shortness of breath, hospitalisation or death. Vaccine effectiveness (%) was calculated as (1-HR)×100. RESULTS: There were 1114 residents (median age 31 years) participating in the study, 82% males. Twenty-eight per cent (n=308/1114) were unvaccinated, 50% (n=554/1114) had received one dose and 23% (n=252/1114) had received two doses of Covishield. The point prevalence of COVID-19 for the facilities ranged from 11% to 57%. Incidence rates (95% CI) of COVID-19 were 76 (63 to 90)/1000 person-months in the unvaccinated, 25 (18 to 35)/1000 person-months in recipients of one dose and 9 (4 to 19)/1000 person-months in recipients of two doses. The effectiveness of first and second doses of Covishield were 71% (adjusted HR (aHR) 0.29; 95% CI 0.18 to 0.46; p<0.001) and 80% (aHR 0.20; 95% CI 0.09 to 0.44; p<0.001), respectively, against SARS-CoV-2 infection and 86% (aHR 0.24; 95% CI 0.07 to 0.82; p=0.023) and 99% (aHR 0.01; 95% CI 0.002 to 0.10; p<0.001), respectively, against unfavourable outcome. The effectiveness was higher after 14 days of receiving the first and second doses, 93% and 98%, respectively. Risk of infection was higher in persons with chronic hepatitis B (aHR 1.78; p=0.034) and previous history of tuberculosis (aHR 1.62; p=0.047). CONCLUSION: Covishield was effective in preventing SARS-CoV-2 infection and reducing disease severity in highly transmissible settings during the second wave of the pandemic driven by the Delta variant.