Unvaccinated people are 11 times more likely to die of COVID-19 and are 10 times more likely to be hospitalised for the infection as compared to those who have been fully vaccinated across 13 jurisdiction areas in the US, according to the US Centers for Disease Control and Prevention
The CDC released a set of studies discussing the effectiveness of the vaccines against the SARS-CoV-2 virus along with its variants including Delta on September 10. These studies were conducted when most hospitals reported that over 50 per cent of their patients had been infected by the Delta variant.
Along with these studies, the apex body also released a study that spoke about the effects and duration of long term COVID-19 symptoms. Close to 66 per cent of the respondents who tested positive reported lasting symptoms for more than four weeks and over 72.6 per cent reported at least one symptom persisting for more than four weeks.
While it was already known that the unvaccinated are at a higher risk of infection, hospitalisation and deaths, the advent of the Delta variant led to many fully vaccinated people reporting testing positive for COVID-19. It, thus became important to find the effectiveness of vaccines to understand the risk of hospitalisations and deaths among the breakthrough infections and the unvaccinated.
The second study found that Moderna was the most effective vaccine from hospitalised patients in the country. The third study found that vaccine immunity waned faster in the age group >65 and thus promoted the use of booster shots in the country. All the studies were released at a time when the Delta variant continues to rapidly transmit across the country with President Biden introducing new vaccine mandates. US reported an average of 1,500 deaths daily in the last week- a trend not seen since March in the country.
Unvaccinated At Higher Risk
The first study that showed the unvaccinated were 11 times more likely to die due to COVID-19 and 10 times more likely to be hospitalised than fully vaccinated people had a very important limitation. The researchers included people who had only received one dose of the mRNA vaccines but included these participants under unvaccinated. Taking note of this caveat, the researchers also conducted a separate analysis where the partially vaccinated were excluded from the study conducted in 13 US jurisdictions between April to July 7, 2021.
Once the partially vaccinated were removed, the unvaccinated were 19 times more likely to die and 15 times more likely to be hospitalised once infected.
Moderna Most Effective
With over 32,867 participants admitted at hospitals, emergency departments and urgent-care clinics across nine states in the months between June to August, this is the largest study checking for vaccine effectiveness in real time.
While the three vaccines were collectively 86 per cent effective in preventing hospitalisation, Moderna had a significantly higher proportion of effectiveness (95 per cent) as compared to Pfizer (80 per cent) and Janssen (60 per cent)
Waning Immunity Among The Elderly
The study conducted between February to August concentrated on the effect of the mRNA vaccines against hospitalisation in 1,175 US war veterans five Veterans Affairs Medical Centers. This is the first study to show that vaccine effectiveness among people over the age of 65 (79.8 per cent) was lower than that seen in the 18-64 age group (95.1 per cent)
This study on waning immunity further boosts the CDC's decision of starting booster shots for the elderly and those who took vaccines eight months ago. The booster shot facility is set to begin for the Pfizer-BioNtech vaccine from September 20.
Long COVID-19 Symptoms Linger In The Population
In a study with 3,000 participants held between April 9-23, 2021, two-third (66 per cent) of the 680 respondents who had tested positive for COVID-19 reported persisting symptoms of COVID-19 for more than 4 weeks. Some of them reported suffering from a headache, losing sense of smell and taste, fatigue, shortness of breath, cough even after testing negative and recovering from the other symptoms.
This study highlights that long term COVID-19 symptoms are now a growing area of concern.