COVID-19 vaccination, risk-compensatory behaviours, and contacts in the UK

The physiological effects of vaccination against SARS-CoV-2 (COVID-19) are well documented, yet the behavioural effects not well known. Risk compensation suggests that gains in personal safety, as a result of vaccination, are offset by increases in risky behaviour, such as socialising, commuting and working outside the home. This is potentially important because transmission of SARS-CoV-2 is driven by contacts, which could be amplified by vaccine-related risk compensation. Here, we show that behaviours were overall unrelated to personal vaccination, but—adjusting for variation in mitigation policies—were responsive to the level of vaccination in the wider population: individuals in the UK were risk compensating when rates of vaccination were rising. This effect was observed across four nations of the UK, each of which varied policies autonomously

Risk of SARS-CoV-2 reinfection during multiple Omicron variant waves in the UK general population

SARS-CoV-2 reinfections increased substantially after Omicron variants emerged. Large-scale community-based comparisons across multiple Omicron waves of reinfection characteristics, risk factors, and protection afforded by previous infection and vaccination, are limited. Here we studied ~45,000 reinfections from the UK’s national COVID-19 Infection Survey and quantified the risk of reinfection in multiple waves, including those driven by BA.1, BA.2, BA.4/5, and BQ.1/CH.1.1/XBB.1.5 variants. Reinfections were associated with lower viral load and lower percentages of self-reporting symptoms compared with first infections. Across multiple Omicron waves, estimated protection against reinfection was significantly higher in those previously infected with more recent than earlier variants, even at the same time from previous infection. Estimated protection against Omicron reinfections decreased over time from the most recent infection if this was the previous or penultimate variant (generally within the preceding year). Those 14–180 days after receiving their most recent vaccination had a lower risk of reinfection than those >180 days from their most recent vaccination. Reinfection risk was independently higher in those aged 30–45 years, and with either low or high viral load in their most recent previous infection. Overall, the risk of Omicron reinfection is high, but with lower severity than first infections; both viral evolution and waning immunity are independently associated with reinfection

Antibody responses to SARS-CoV-2 vaccines in 45,965 adults from the general population of the United Kingdom

We report that in a cohort of 45,965 adults, who were receiving either the ChAdOx1 or the BNT162b2 SARS-CoV-2 vaccines, in those who had no prior infection with SARS-CoV-2, seroconversion rates and quantitative antibody levels after a single dose were lower in older individuals, especially in those aged >60 years. Two vaccine doses achieved high responses across all ages. Antibody levels increased more slowly and to lower levels with a single dose of ChAdOx1 compared with a single dose of BNT162b2, but waned following a single dose of BNT162b2 in older individuals. In descriptive latent class models, we identified four responder subgroups, including a ‘low responder’ group that more commonly consisted of people aged >75 years, males and individuals with long-term health conditions. Given our findings, we propose that available vaccines should be prioritized for those not previously infected and that second doses should be prioritized for individuals aged >60 years. Further data are needed to better understand the extent to which quantitative antibody responses are associated with vaccine-mediated protection

Antibody responses and correlates of protection in the general population after two doses of the ChAdOx1 or BNT162b2 vaccines

Antibody responses are an important part of immunity after Coronavirus Disease 2019 (COVID-19) vaccination. However, antibody trajectories and the associated duration of protection after a second vaccine dose remain unclear. In this study, we investigated anti-spike IgG antibody responses and correlates of protection after second doses of ChAdOx1 or BNT162b2 vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the United Kingdom general population. In 222,493 individuals, we found significant boosting of anti-spike IgG by the second doses of both vaccines in all ages and using different dosing intervals, including the 3-week interval for BNT162b2. After second vaccination, BNT162b2 generated higher peak levels than ChAdOX1. Older individuals and males had lower peak levels with BNT162b2 but not ChAdOx1, whereas declines were similar across ages and sexes with ChAdOX1 or BNT162b2. Prior infection significantly increased antibody peak level and half-life with both vaccines. Anti-spike IgG levels were associated with protection from infection after vaccination and, to an even greater degree, after prior infection. At least 67% protection against infection was estimated to last for 2–3 months after two ChAdOx1 doses, for 5–8 months after two BNT162b2 doses in those without prior infection and for 1–2 years for those unvaccinated after natural infection. A third booster dose might be needed, prioritized to ChAdOx1 recipients and those more clinically vulnerable

SARS-CoV-2 antibody trajectories after a single COVID-19 vaccination with and without prior infection

Given high SARS-CoV-2 incidence, coupled with slow and inequitable vaccine roll-out in many settings, there is a need for evidence to underpin optimum vaccine deployment, aiming to maximise global population immunity. We evaluate whether a single vaccination in individuals who have already been infected with SARS-CoV-2 generates similar initial and subsequent antibody responses to two vaccinations in those without prior infection. We compared anti-spike IgG antibody responses after a single vaccination with ChAdOx1, BNT162b2, or mRNA-1273 SARS-CoV-2 vaccines in the COVID-19 Infection Survey in the UK general population. In 100,849 adults median (50 (IQR: 37–63) years) receiving at least one vaccination, 13,404 (13.3%) had serological/PCR evidence of prior infection. Prior infection significantly boosted antibody responses, producing higher peak levels and/or longer half-lives after one dose of all three vaccines than those without prior infection receiving one or two vaccinations. In those with prior infection, the median time above the positivity threshold was >1 year after the first vaccination. Single-dose vaccination targeted to those previously infected may provide at least as good protection to two-dose vaccination among those without previous infection

Protection against SARS-CoV-2 Omicron BA.4/5 variant following booster vaccination or breakthrough infection in the UK

Following primary SARS-CoV-2 vaccination, whether boosters or breakthrough infections provide greater protection against SARS-CoV-2 infection is incompletely understood. Here we investigated SARS-CoV-2 antibody correlates of protection against new Omicron BA.4/5 (re-)infections and anti-spike IgG antibody trajectories after a third/booster vaccination or breakthrough infection following second vaccination in 154,149 adults ≥18 y from the United Kingdom general population. Higher antibody levels were associated with increased protection against Omicron BA.4/5 infection and breakthrough infections were associated with higher levels of protection at any given antibody level than boosters. Breakthrough infections generated similar antibody levels to boosters, and the subsequent antibody declines were slightly slower than after boosters. Together our findings show breakthrough infection provides longer-lasting protection against further infections than booster vaccinations. Our findings, considered alongside the risks of severe infection and long-term consequences of infection, have important implications for vaccine policy

Common Ocular Morbidity among Elderly: A Study in a Slum of Kolkata, West Bengal

Background: Life expectancy of Indian population is gradually increasing day by day as a consequence of which proportion of elderly people living in India is also increasing. In spite of a National Program on control of blindness, there is huge number of elderly people who are blind often due to avoidable and preventable causes. Objective: The objective of this study is to find out the proportion of common ocular morbidity and associated factors among elderly population in a slum at Chetla, Kolkata. Materials and Methods: It was a community-based observational study cross-sectional in design carried out in a slum of Kolkata among elderly population of age ≥60 years residing at Chetla. The calculated sample size was 154, and the study was conducted for a period of 3 months. Results: Among the study participants, ocular morbidity was 73 (47.4%). 44 (28.5%) were diagnosed to have cataract followed by 31 (20.1%) having visual impairment Category 1 and 18 (11.6%) Category 2, in univariate logistic regression, significant association was found between ocular morbidity with age odds ratio (OR) (confidence interval [CI]) 2.44 (1.25–4.73), sex OR (CI) 4.63 (2.34–9.15), education OR (CI) 2.55 (1.32–4.91), economic dependency OR (CI) 5.47 (2.72-11.03), and PCI OR (CI) 2.11 (1.11–4.02). In final, multivariable logistic regression significant association was found with age-adjusted odds ratio (AOR) (CI) 3.70 (1.64–8.35), sex AOR (CI) 3.22 (1.28–8.10), and economic dependency AOR (CI) 2.83 (1.03–7.76). Conclusion: Majority of causes of blindness among the study group in this survey was avoidable, cataract being the leading cause. Government initiatives such as ensuring good quality geriatric eye health-care services at the primary level with cataract operation facilities and health education to raise awareness about preventable and curable eye diseases would further help to tackle this preventable disease burden of the elderly. This will contribute whole heartedly to marked improvement of the quality of life of the elderly population of India

Is Ramadan Fasting Cardio-protective? A Study in a Village of West Bengal

Background: Islam is the second largest religion of the World (23%) and Muslims are the second largest majority of Indian Republic (14.3%). Ramadan is the ninth and holiest month(Hijra) of the 12-month Islamic calendar during which Muslims fast from dawn to dusk each day maintaining certain rules (consuming food/drink once, avoiding smoking and sexual activity, as well as impure thoughts, words and immoral behavior). It is observed by Muslims as a month of fasting to commemorate the first revelation of the Qur'an to Muhammad. Aims & Objectives: To evaluate the effect of Ramadan on cardio-metabolic profile among adult Muslims residing in rural West Bengal. Methods and Materials: The present study was a longitudinal community based study done among 43 Muslims residing in a village of West Bengal during 6thJune to 7th July 2016. Cardio-metabolic profile (physical activity, diet, BMI, blood pressure, blood lipids and glucose) were assessed before, during and after Ramadan. Results: There was a significant reduction in VLDL and TG level while significant elevation in HDL level along with the reduction in Framingham risk score after fasting. All the anthropometric measurements along with blood pressure reduced significantly after Ramadan with significant reduction in intake of all micro-nutrients during Ramadan. However physical activity also reduced significantly during Ramadan. Conclusion: Our study had found no detrimental effects of Ramadan fasting on the contrary has an overall beneficial effect on cardiovascular profile was observed

Anti-spike antibody response to natural SARS-CoV-2 infection in the general population

Understanding the trajectory, duration, and determinants of antibody responses after SARS-CoV-2 infection can inform subsequent protection and risk of reinfection, however large-scale representative studies are limited. Here we estimated antibody response after SARS-CoV-2 infection in the general population using representative data from 7,256 United Kingdom COVID-19 infection survey participants who had positive swab SARS-CoV-2 PCR tests from 26-April-2020 to 14-June-2021. A latent class model classified 24% of participants as ‘non-responders’ not developing anti-spike antibodies, who were older, had higher SARS-CoV-2 cycle threshold values during infection (i.e. lower viral burden), and less frequently reported any symptoms. Among those who seroconverted, using Bayesian linear mixed models, the estimated anti-spike IgG peak level was 7.3-fold higher than the level previously associated with 50% protection against reinfection, with higher peak levels in older participants and those of non-white ethnicity. The estimated anti-spike IgG half-life was 184 days, being longer in females and those of white ethnicity. We estimated antibody levels associated with protection against reinfection likely last 1.5-2 years on average, with levels associated with protection from severe infection present for several years. These estimates could inform planning for vaccination booster strategies