[ad_1]
England has achieved relatively high vaccination coverage with at least one dose of the vaccine having been given to three in four citizens, for the age groups 18 and over. This is good news for the country, which has been hit hard by the 2019 coronavirus disease (COVID-19) since March 2020.
A new study reports this finding, along with the varying prevalence of antibodies between different groups and regions and between different age groups. In this document, available as a preprint on the medRxiv * server, the results of the sixth cycle of the REACT-2 study are reported.
In previous cycles, widely varying COVID-19 prevalence rates by region, ethnicity and occupation have been reported. In subsequent cycles, seroprevalence gradually decreased, as antibody levels decreased, but then increased again, due to the second wave of viral spread as well as increased vaccine coverage.
The current cycle was carried out from May 12 to 25, 2021, covering more than 207,000 adults who have self-tested using the LFA. This number includes less than a third of the guests, but more than 80% of all who signed up for the test.
Background
REACT-2 (REal-time Assessment of Community Transmission-2) is a cross-sectional randomized community survey of adults in England, which has been taking place in England since the early days of the pandemic caused by the severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2).
The methods include questionnaires to trigger symptomatic infections coupled with lateral flow immunoassay (LFA) tests to detect evidence of past or current infection. The detection of immunoglobulin G (IgG) antibodies against the SARS-CoV-2 spike protein was used as an indicator of the prevalence of infection before the start of the vaccination program.
The rollout of the COVID-19 vaccine in England began in December 2020, in a phased manner, prioritizing those most at risk of infection and severe symptomatic illness. The rapid implementation of the vaccination program occurred, assisted by the introduction of a practice of second dose delayed to 12 weeks after the first. By July 2021, 85% of adults in England had received one dose, and nearly two in three had received both doses.
Evidence is mounting that rapid vaccination coverage has helped reduce the transmission of SARS-CoV-2, reduce hospitalizations and the death rate from COVID-19.
Immunization coverage
The researchers found that among the study sample, about 73% of adults had been vaccinated with at least one dose. However, this only included a quarter of 18-24 year olds, but almost all those aged 75 or over.
Health workers were about ten times more likely to be vaccinated, and caregivers four times, compared to non-essential workers, while those in education were 63% more likely to increase compared to other areas of work. Unfortunately, workers in the hospitality and retail industries, who should have contact with the public, were about 30% less likely to have immunization coverage than other workers.
Even so, men were 10% less likely to have been vaccinated than women, while blacks were 60% less likely to have received the vaccine. Conversely, Asians had 13% higher odds.
Socio-economic deprivation was also inversely related to vaccine coverage, and those who said they had previously had COVID-19 were 40% less likely to be vaccinated. Londoners were 14% less likely to be vaccinated, while those in North West England were 23% more likely to be vaccinated compared to South East England.
What about vaccine hesitation?
Scientists found that about 98% of participants said they had been or intended to be vaccinated when they became eligible. The percentage of hesitation or refusal to get vaccinated has decreased in all age groups, with less than 1% of people identifying themselves as such.
The most reluctant were the 25-34 year olds, with 25% more hesitation than the 35-44 year olds. Poorer and less educated people also showed somewhat more reluctance, as did those of black or mixed ethnicity, compared to people of Caucasian or Asian descent.
A history of COVID-19 or smoking has also increased the risk of hesitation. Overall, the most common reasons given for reluctance were fear of long-term side effects or a desire for evidence of the vaccine’s effectiveness. However, this reason was cited less often in this cycle compared to previous cycles.
What was the prevalence of antibodies?
The results showed that the prevalence of antibodies increased remarkably following the implementation of the vaccination. The increase to 61% contrasts with 14% and <7% in the previous two rounds. The lowest prevalence was in the North West, at 58%, compared to 62% among Londoners.
Taking local communities individually, the variation was larger, from 40% to 79%. Healthcare workers were eight times more likely to be HIV positive than other workers or non-essential workers, while healthcare workers were four times more likely. Essential workers were 30% more likely than other non-essential workers.
Again, age predicted a higher seroprevalence, with 95% of people aged 75 or older showing anti-spike antibodies compared to 36% of people aged 18 to 24. This trend, reflecting immunization coverage, persisted with regard to ethnicity, with Asians showing 67%, blacks 55%, but mixed 17%, and other races 37% more likely to be HIV-positive.
However, men were 30% less likely to be HIV positive, but deprivation did not show a significant effect in this area. Hospitality and retail workers were 30-40% less likely to be positive for antibodies.
Post-vaccination antibody positivity
Antibody positivity increased after the first and second doses, decreasing 4 to 5 weeks after the first dose, lasting up to 11 weeks. Positivity was higher in people with a history of infection, and people who received the Pfizer vaccine also had a higher likelihood of being HIV positive compared to the Astra-Zeneca vaccine.
After two doses, the Pfizer vaccine was associated with 100% seropositivity at all ages except 80 years and older, with this group showing 98% positivity. With the AstraZeneca vaccine, about 90% or more of people up to age 79 were HIV positive, compared to 84% of older people.
Single dose positivity ranged from 100% in 18-29 year olds to 32% in 70-79 year old for the Pfizer vaccine. In contrast, the Astra-Zeneca vaccine produced 72% seropositivity among the youngest, but only 46% among those 80 and over in the group. A few have received the Moderna vaccine with high rates of HIV infection.
What are the implications?
The study shows that vaccination was implemented rapidly and on a large scale in England in adults, producing a relatively higher prevalence of antibodies after two doses of the vaccine. The lowest coverage is for the youngest eligible group, which has the lowest vaccine priority, as well as some disadvantaged groups, among men and those living in London.
Among workers facing the public, vaccination coverage and seroprevalence were low, indicating that they remain at a higher risk of infection and can therefore transmit infection. People with a history of COVID-19 had lower coverage, perhaps because a four-week delay is recommended in this group or because these people already feel immune.
A satisfactory increase in the prevalence of antibodies is observed after 70% coverage with at least one dose of a COVID-19 vaccine. The increase is most marked after the second dose, implying that both doses should be taken when offered. The dramatic increase after the second dose, especially as antibody titers drop between weeks 4 to 11 after the first dose, confirms the need to reduce the period between the first and second dose during a period of spread. fast.
More research is needed to establish the link between being positive for IgG against the virus and the ability to neutralize, which alone can hinder infection and transmission. It is also possible that emerging variants such as the delta strain will not be neutralized unless high protective antibody titers are achieved.
Deprivation is linked to lower vaccination coverage, while non-white ethnicity was associated with higher HIV status due to a greater risk of infection. Overall, the encouraging vaccination rates and HIV prevalence are favored by lower antibody coverage and prevalence in some groups.
Improving vaccination rates in these groups is essential to achieve high levels of protection against the virus through population immunity,», Underline the authors.
*Important Notice
medRxiv publishes preliminary scientific reports which are not peer reviewed and, therefore, should not be considered conclusive, guide clinical practice / health-related behavior, or treated as established information.
Source link
