On breakthrough infections, vaccines and gap between doses:

A correspondence published in NEJM on 2nd June, details a study on breakthrough infections with a large cohort of 7000+ healthcare workers in a tertiary hospital in India.

nejm.org/doi/full/10.10…

1/n
7000+ received the first dose and 3600+ of them subsequently got the 2nd dose.
Vaccine administered was Covishield.
An additional 5000+ were not vaccinated.

Study period: Jan-Apr 2021.

📌 506 HCWs tested +ve during the study, of which 64% were unvaccinated.

2/n
📌 Of the 7000+ HCWs that got the 1st dose, only 2.6% of them tested positive.
📌 3600+ HCWs got both doses and 2% of them tested positive.
📌 Breakthrough infection, measured as those testing positive 14 days after both doses stood at 1.6%.

3/n
These results point to two important conclusions:

a. Vaccines do provide significant protection against symptomatic infection.
b. While vaccines protect, there can be cases of infection even after 2 doses.

This brings us to the question of variants and vaccine efficacy.

4/n
A key paper from the UK exploring the effectiveness of AstraZeneca (Covishield) and Pfizer vaccines, on variants of concerns, showed significant drop in efficacy for a single dose against the Delta (B.1.617.2) variant.

medrxiv.org/content/10.110…

5/n
Efficacy after 2 doses saw a dip to 60% for Covishield with the B.1.617.2 variant.

📢 Key summary:

✅ B.1.617.2 variant lowers the vaccine efficacy, yet provides significant protection compared to not taking the vaccine.
✅ Efficacy for a single dose dropped to 33%.

6/n
✅ Getting the 2nd dose is critical to provide higher protection with the Delta variant.
✅ A recent genome sequencing study by AIIMS-IGIB on 63 cases of breakthrough infections showed B.1.617.2 to be the dominant variant among the breakthrough cases.
osf.io/fgd4x/

7/n
✅ A key observation from all these studies is that those who got both doses of the vaccine did not experience severe covid or death.

📌 Key implications:

✅ If single dose of vaccine has a lower efficacy against the new variant, should the gap between doses be reduced?

8/n
Excerpt from a recent paper in The Lancet:

"These data therefore suggest that the benefits of delaying the second dose, in terms of wider population coverage, must now be weighed against decreased efficacy in the short-term, in the context of the spread of B.1.617.2."

9/n
✅ Excerpt from same article highlighting the need to speed up the 2nd dose.

"Worldwide, our data highlight the ongoing need to increase vaccine supply to allow all countries to extend second-dose protection as quickly as possible."

thelancet.com/journals/lance…

10/n
✅ We had recently increased the gap between 2 doses of Covishield to 12 - 16 weeks. While trial data suggested an improved efficacy with a delay of 90 days, emerging evidence points to the importance of the 2nd dose against the new dominant variant.

11/n
✅ Emerging data points to the risk of a delayed 2nd dose in the context of the Delta variant. A balance will have to be struck between providing improved protection with 2 doses and covering more persons with 1 dose. In all of this, vaccine availability is the key.

12/n
✅ Lastly, this highlights the importance of genetic sequencing to identify variants of concern and using that data to guide our pandemic response.

Our response to the 2nd wave might have been different if the nature of the B.1.617 variants were acknowledged earlier.

n/n

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More from @covid19indiaorg

4 Jun
Have questions on Covid19 recovery?
We answer the most important ones in this master thread. #stayaware

❓Is a #Covid test required to confirm recovery?

If you do not have any symptoms 14 days after confirmation of Covid, a repeat test IS NOT required.

1/n
❓When can I consider myself recovered from Covid?

➡️ 14 days after date of test.
➡️ 3 consecutive days of no symptoms.
➡️ If you had severe symptoms, consult your doctor for discharge criteria.
➡️ No need for a repeat RTPCR test.

2/n
❓Do I need to continue wearing masks inside my home after recovery?

No. One does not generally transmit the virus after Day 10 of infection. After 14 days of room quarantine, there is no need to wear a #mask inside the house.

3/n
Read 15 tweets
3 Jun
A quick overview of Biological E.'s Covid vaccine:

✅ Vaccine platform: Protein Subunit.
✅ Number of doses: 2 doses
✅ Gap between doses: 28 days*
✅ Current status: Completed Phase 1 and 2 trials. Got approval for Phase 3 trials in April 2021.

*As per clinical trials.

1/n
✅ Partnership: Antigen developed by Texas Children's Hospital for Vaccine Development and Baylor College of Medicine. Adjuvant supplied by Dynavax Technologies (US).

✅ Proven platform used for Hepatitis B vaccine. Novavax vaccine also uses subunit technology.

2/n
✅ What is a protein subunit vaccine?
It consists of specific parts of the SARS-Cov-2 antigen that are synthesized and harvested in a medium like yeast. The proteins themselves elicit weak immune response and they need an adjuvant added to augment the immune response.

3/n
Read 6 tweets
2 Jun
Q&A from the doctor's desk 🩺 #stayaware

❓I am feeding my 9 month old baby. Can I take the vaccine?

Yes. As per latest MoHFW guidelines, lactating mothers can take the vaccine. Go ahead!

1/n
❓My mother turned negative for Covid 2 weeks back. When can she take the vaccine?

She can take the vaccine 3 months after recovery. Ensure she follows all Covid safety precautions now as well as after vaccination!

2/n
❓ Is there any side effect of taking vitamin C for over a month?

No, but there is no benefit as well. Maintaining balanced diet and drinking adequate water will be more beneficial than taking supplements, as long as you do not have specific deficiencies.

3/n
Read 11 tweets
2 Jun
One of our most active initiatives right now is the free Medical Help group.

Few observations:
✅ Significant requests from non-urban locations.

✅ Together with drop in cases, query volume has dropped as well.

✅ Now most queries are on vaccination and mucormycosis.

1/3
✅ Large number of queries were on symptoms, knowing when to test, hospitalize, sos prescription etc.

✅ Considering that majority will recover from home, accessible teleconsultation services should be looked at as an effective tool going forward.

2/3
✅ We've seen significant impact with this initiative, especially for those from rural locations.

✅ Teleconsultation services should be made available in EVERY DISTRICT as a first line intervention.

Link to group t.me/CovidMedHelp

3/3
Read 4 tweets
1 Jun
As Covid spread to rural India, can you help build awareness?

Here are #Covid19 awareness posters in 6 vernacular languages:

✅ Hindi, Bengali, Kannada, Malayalam, Odia and Tamil.

Awareness can save lives.
Share the word.
Help save lives!

#COVID #COVID19India ImageImageImageImage
#bengali
Stay aware about Corona.
Awareness can save lives. Help spread the word. Help save lives. ImageImageImageImage
#kannada
Stay aware about Corona.
Awareness can save lives. Help spread the word. Help save lives. ImageImageImageImage
Read 7 tweets
1 Jun
Will our vaccination numbers rebound this month?

With 5.8Cr doses, May saw a 35% DROP in vaccine doses administered, compared to April.

As per official data, vaccine supply stood at 7.94Cr doses in May.

Then, why were we able to administer only 5.8Cr doses?

1/4 Image
📌 Data as on 29th May morning, shows that states had 2.15Cr doses available with them. Together with the 5.8Cr administered doses, this accounts for the 7.94Cr monthly supply figure.

📌 Does this mean that states have had stock, but vaccination was slow? Let's explore:

2/4 Image
As per official data 1.43Cr doses were available with states as of 22/05.
Between 22/05 and 28/05, 1.38Cr doses were administered by states: A high utilisation %.

If 2.15Cr doses were available as of 29/05, it points to 2Cr+ doses being supplied in the last week of May.

3/5 Image
Read 6 tweets

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