Transparent science communication to the general public.

Today’s Manorama paper carried a fact-based advisory about potential post-Onam surge in Kerala by @RajeevJayadevan & others at IMA Cochin.

In Kerala, Onam is a festival that everyone celebrates.

Detailed thread 👇1/16
This advisory comes from numerous Tuesday meetings of experts held by IMA Cochin - ever since the start of the pandemic where we continuously monitor events locally, nationally as well as around the world.

We have given out advisories in the past which helped policymakers👇

2/
This timeline shows Kerala‘s pandemic of contrasting with the national average. The only surge in 2020 was in October, see graphs.

The number of cases in October 2020 was 6 times that of August 2020.

However in 2021, the “baseline” number of cases is 12 times that of 2020.

3/
This means that if the current number goes up by a few multiples, the healthcare system could come under strain. We hope that it will not happen - with continued advisories given to the public as well as policymakers.

We have outlined the following steps to reduce the surge.

4/
At this time, since there are no mass gatherings, most of the transmission is occurring quietly in closed settings - such as individual homes and workplace.

We know from published literature that more than 50% of transmission occurs through asymptomatic individuals.

5/
People who go to work bring virus from outside and infect those who are sitting at home, some of whom are unvaccinated.

Social distancing and mask wearing are practically ~impossible to implement at home.

The Delta virus spreads fast and has higher secondary attack rate.

6/
Secondary attack rate refers to the number of people that get infected from the first patient.

Eg. Attack rate of 50% means that 2 out of 4 members in a household will get infected.

On the ground, we are often seeing attack rates of close to 100% - with the delta variant.

7/
Human behaviour is a driving force in the pandemic. Unfortunately vaccination encourages people to disregard standard precautions.

Many of these people believe that they will never pick up the virus- which is not true. We know that breakthrough infections occur.

8/
Such individuals tend to socialise more, believing that it is safe to do so.

A few of them pick up the virus in the nose and throat, which they pass around during small social gatherings.

While they may not get sick, a vulnerable person who is older might become a victim.

9/
Fortunately, Kerala‘s vaccination coverage is 84% (1 dose) and 41% (2 doses) in the susceptible age group - that is greater than 45 years of age.

This has kept the % of hospitalisations down, as people are not getting severely ill in large numbers.

10/
That is the reason why in spite of Kerala having 12 times the number of COVID-19 patients compared to the same date a year ago, the hospitals are still running smoothly.

In other words the virus is continuing to infect people, but the % or proportion getting sick is small.

11/
The concept of social bubble important, and communicating this to the general public is not easy. The following diagram helps explain it.

“Social bubble” refers to the people we are regularly in contact with.

Unfortunately we don’t live in bubbles.

12/
Unless we are consciously aware of multiple bubbles around us, it becomes possible for a virus located in a bubble far away to find its way to our home or work place.

Socialisation increases this risk.

For people who work in healthcare/public places, the bubble is large.

13/
Therefore during the during the festive season we have advised people to stick to the minimum social bubble possible - and to reduce social visits.

🔺Even one extra social visit per family can multiply the spread of the virus during the season.

14/
We believe that next year, Onam will find us in a much better situation- with close to 100% of individuals having some form of immunity either through vaccination or through natural infection.

Thus, during future waves, the % of people getting sick will be smaller.

15/
The risk of spread is much lower in open spaces, this principle must be utilised.

The risk of spread is greater indoors. Therefore, systematic efforts must be made to improve ventilation and air circulation after consulting experts such as architects/engineers.

16/
The timing of opening of shops and other public places must be extended so that people have the option of shopping when it is less crowded.

Reducing opening hours will only increase crowding.

17/17

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More from @RajeevJayadevan

17 Sep
Past infection did not provide additional protection from breakthrough infections.

ICMR study on 614 healthcare workers, half of whom each got covishield & covaxin.

Breakthrough infection rate was 13% in those with & without past infection.

1/6

assets.researchsquare.com/files/rs-88876… Image
Breakthrough infection rate is not provided for type of vaccine. Only overall number is given (13%, 81/614)

Antibody levels are seen to drop with time as expected.

Peak antibody levels are lower & the decline faster for covaxin, but this does not imply lower protection.

2/
The reason why a lower antibody level does not mean lower protection is that there are multiple components in the immune system that provide protection. Not all of them are measurable.

Besides, the study does not provide data that lower antibody level led to more infections.

3/
Read 7 tweets
16 Sep
Multiple issues with the widely quoted NEJM Israel study on boosters

Long thread👇

1. Authors report a lofty reduction in infections & severe cases by a factor of 11.3 & 19.5 in the primary analysis, where rates are compared between boosted & non boosted groups.

But ...

1/
2. In secondary analysis, this factor is down to 5.4. Secondary analysis compares rates within the SAME group, by timeframe. This is more believable not only because comparison is within the same group, but also because we know higher antibody levels reduce infection rates.

2/
Note: secondary analysis is available ONLY for infections, not severe cases.

In other words, we do not yet know if this 5.4-fold reduction in ‘infection’ will translate to reduction in hospitalisation/death later.

3. No mention of number of people who were hospitalised.

3/
Read 12 tweets
13 Sep
Detailed graphical representation of the story of the US elementary school teacher who infected 12 of her masked students by reading aloud without mask.

Lessons:

1. Multiple factors have to be in place to prevent outbreaks

2. Aerosol spread infects people both near & far

1/ Image
3. Masks did not protect the children from getting infected.

4. The teacher was unvaccinated, and had attended social gatherings.

5. She developed mild “allergy” symptoms which she chose to ignore (this could happen to anyone: wisdom is easier in hindsight)

2/ Image
6. Children in the next classroom also got infected, showing how far aerosols can travel

7. This also shows physical spacing is of limited value (think cigarette smoke in a room, spacing doesn’t change how the smoke spreads or smells)

3/
Read 6 tweets
28 Aug
Natural infection provides greater protection than (Pfizer) vaccination

Large study from Israel compared 3 groups of people

1. Past infection
2. Pfizer-vaccinated individuals
3. Those who had both

Please see WHOLE thread👇

1/
Large cohort of 673,676 vaccinated, 62883 past infection, & 42,099 vacc + past infection. The groups were matched to exclude confounding.

They looked at remote & recent past infection separately. Those who were infected in 2021 had greater protection than 1 year ago.

2/
The vaccinated group had a 27-fold greater risk of SYMPTOMATIC breakthrough infection compared to natural infection. The risk was 13-fold for ALL breakthrough infections.

A single dose of vaccine further increased the level of protection for those who had past infection.

3/
Read 14 tweets
26 Aug
Vaccines prevent deaths.

Audit of 281 COVID-19 deaths in Ernakulam showed that 98.2% of the deaths occurred among those who had not been (fully) vaccinated. i.e. only 1.8% of deaths were fully vaccinated.

@RajeevJayadevan Quoted in The Hindu today.

thehindu.com/news/cities/Ko…
🔺All deaths among the fully vaccinated, occurred in people older than 60.

The current vaccination coverage in adults is 68% (1 dose) & 24% (2 doses)

We can say the % of fully vaccinated is 24%, yet deaths in that category was only 1.8% - that is 92.5% lower than expected.

2/
These figures from death audits aren’t enough to calculate vaccine effectiveness.

But when we compare with current vaccination coverage, we get an idea of how much lower the deaths are among the fully vaccinated.

1.8% (observed rate) is 92.5% lower than 24% (expected rate*)

3/
Read 7 tweets
18 Aug
The reason why children are easily able to get rid of the SARS-CoV-2 virus is due to a super-efficient innate immune system in their airways, as was hypothesised earlier (not from ‘less ACE2 receptors’).

Innate immunity is our “rapid response unit”.

1/4

nature.com/articles/s4158…
Innate immunity refers to those defence mechanisms that are the “first responders”- even before an exact ID of the attacker is known.

Adults respond less efficiently.

As a result, there is an imbalance between the various departments of our immune system, which isn’t good.

2/
SARS-CoV-2 virus is super-replicating, and turns off our innate immunity early (interferons are part of this) to aid the “stealth factor”.

It is harder to do so in children - who have a hyper-alert system that outperforms adults in the 1st 4 days of infection, authors find.

3/
Read 4 tweets

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