Some good news for your morning! A recent study out of India shows:
•Both Covishield (AstraZeneca) and Covaxin prompted good immune response after two doses
•95% of participants (N=515, HCWs) showed seropositivity (higher antibodies) after two doses of either vaccine
•A total of 27 breakthrough infections (4.9%) were recorded among respondents who had received both doses of either of the vaccines. Out of these, 25 were mild and two were moderate cases of breakthrough infections
•NO deaths were recorded as a result of breakthrough infections
•Seropositivity rates and median anti-spike antibody titre was significantly higher in Covishield (AstraZeneca) recipients
•Of the 425 Covishield (AstraZeneca) and 90 Covaxin recipients, 98.1% and 80% respectively, showed seropositivity
•NOTE: While no difference was observed in relation to gender, body mass index, blood group and any comorbidities, people aged 60 years and above or those with type 2 diabetes had a significantly lower seropositivity rate, indicating a comparatively lower antibody response
•Unpublished data had earlier indicated Covishield was found to be 70% effective after the FIRST dose
•At the same time, preliminary data from its Phase III trial put Covaxin's efficacy rate at 81%
•Another NOTE: anti-spike antibody level is NOT the same as neutralizing antibody titers (NAb). Neutralizing antibody titers actually form only a fraction of the total anti-spike antibodies produced
According to the authors, the study showed a good safety profile for both vaccines and that the vaccines are indeed working. They further underscored the need to speed up vaccinations to avert any potential waves of infections by expanding the coverage of vaccinations.
I figured it was best to make a comprehensive thread concerning the study out of The Lancet concerning variant B.1.617.2 (Delta) after mRNA vaccination to help clear up some confusion. Most aren’t breaking it down into layman’s terms, so allow me. Let’s discuss.
Firstly, 250 people, one study, one assay. Median age was 42, fairly healthy. We have established the evasiveness of B.1.617.2 is similar to B.1.351. Got it? Okay, good. I’ll make this simple and put it into bullet points. Study can be found here: thelancet.com/journals/lance…
•One dose is not enough, two are needed for high levels of nAbs. Yes, we knew this. It also falls in line with PHE data from last week
•EXTREMELY IMPORTANT TO NOTE: Antibody neutralization is NOT the same as vaccine efficacy, as in a 5.8-fold reduction in antibody
This is fantastic! Real-world data out of Butantan Institute São Paulo, Brazil shows after ~75% of Serrana’s population had been vaccinated with Coronavac:
•95% reduction in deaths
•86% reduction in hospitalizations
•90% reduction in IC
•80% reduction in symptomatic cases
Total vaccinated population: 27,150 (97.7% of adult population vaccinated with first dose; 95% vaccinated with second dose). Keep in mind, this is in the face of variants of concern including P.1. 75% of Serrana’s population had been vaccinated with Coronavac from February-April.
For comparison purposes, Serrana was compared with Jardinópolis, a nearby city. The death curves were similar UNTIL Serrana began vaccinating. After vaccination (first graphic), we can see deaths rose in Jardinópolis (blue) but dropped significantly in Serrana (orange).
This is so encouraging! A recent study demonstrates detection and longitudinal persistence of SARS-CoV-2 IgG antibodies in the upper respiratory tract following COVID-19 vaccination. What does this mean? Prevention of SARS-CoV-2 infection AND transmission! Let’s discuss!
Researchers enrolled 114 individuals who had received their first dose of Moderna’s vaccine within 3-7 days and collected oral mucosal fluid samples on days 5, 10, 15, and 20 after each vaccine dose. Of those who were naive (no history of previous infection) to SARS-CoV-2
(n = 89), 79 (85.4%) tested positive for SARS-CoV-2 IgG antibodies by time point 2 (10 days +/-2 days after first vaccine dose), and 100% tested positive for SARS-CoV-2 IgG by time point 3 (15 days +/-2 days after first vaccine dose). And that’s with just one dose!
Immunological memory for the win! Two new studies show immunity to Coronavirus lasts AT LEAST a year, possibly a lifetime, AND improves over time, ESPECIALLY when paired with vaccination!
The first study shows those who had been previously had an infection have cells that retain a memory of the virus persist in their bone marrow and produce antibodies whenever needed, demonstrating a SARS-CoV-2 infection induces a robust antigen-specific,
long-lived humoral immune response in humans. Find that study here: nytimes.com/2021/05/26/hea…. The second study is still being reviewed before publication in Nature but found memory B-cells continue to mature and strengthen for at least 12 months after initial infection!
A study from Indraprastha Apollo Hospital in Delhi on 69 HCWs vaccinated with Covishield (AZ) who tested positive post vaccination shows:
•Vaccines helped prevent severe illness and hospitalization
•NO deaths, NO ICU admissions
•B.1.617.2 was sequenced in 48% of cases
Amongst the 69 HCWs, 51 were fully vaccinated with two doses (74%) and the remaining 18 (26%) were partially immunized with a single dose, prior to being infected. The predominant infections occurred from B.1.617.2 lineage (48%), followed by B.1 and B.1.1.7 strains.
There were only two hospital admissions (2.9%) for minor symptoms, but NO ICU admissions and NO deaths, from this group. These findings are significant because more than half of the cohort were found infected with B.1.617.2 and were still protected from severe illness,
Let’s clear up some confusion. Concerning AstraZeneca against B.1.617.2 and those reporting it is only 60% effective, let’s stop. It’s ONLY 60% at 21 days post-second dose follow-up. At the 11-12 week follow up, one would expect it to be closer to 80-90% range. Why? See here.
Also, NO, it doesn’t take AstraZeneca 12 weeks post-second dose to achieve efficacy either. So don’t get confused. Remember that rollout of second doses of AstraZeneca was later than Pfizer in the UK. In this PHE analysis from last night, most (74%) people had only just recently
(past 28 days) had their 2nd AZ doses, vs. less than half (46%) of Pfizer, and half of them had it more than 28 days ago. So for example, B.1.1.7, when you’re looking at this chart. AstraZeneca 2 doses after 28 days is 66%. AstraZeneca second dose AFTER 12 weeks is 85-90%.