I'm following this wonderful discussion.

I think it just boosts your immunity but does not give guaranteed protection against COVID. Only helps to fight the disease maybe.

It could help in protection of many diseases not only COVID-19 depends upon ingredients but it doesn't mean this should take more frequently. One or two times a day is enough.

very interesting question

Agree with Anoop Kumar sir.

Does kadha really work in COVID-19? An interesting topic but not much scientific evidence.

I did not find any articles any where except from India about herbal drink kadha regarding its' immune boosting properties. No randomised controlled trial is done in patients with COVID-19.

However, these articles from scientic and lay press discuss about it.

Deleted research item The research item mentioned here has been deleted

Preprint Evaluation of Traditional Ayurvedic Preparation for Preventi...

https://indianexpress.com/article/lifestyle/food-wine/covid-survivor-immunity-boosting-kadha-easy-recipe-inside-6487245/

Immunity is the only hope till date, as we have no vaccine, Its extracts arereported that it has potential to boost up immune response, still further research is needed world wide

https://m.timesofindia.com/life-style/food-news/recipe-of-the-immunity-boosting-kadha-shared-by-a-covid-19-survivor-becomes-viral/amp_etphotostory/76859329.cms

Please see the links below.

https://www.india.com/lifestyle/tried-and-tested-immunity-boosting-kadha-that-helped-a-covid-19-patient-combat-the-condition-4079561/

https://food.ndtv.com/food-drinks/kadha-for-immunity-prepare-this-herbal-potion-with-basic-indian-herbs-and-spices-2249065

Agree with Muhammad Yousuf

https://www.google.com/amp/s/www.india.com/lifestyle/tried-and-tested-immunity-boosting-kadha-that-helped-a-covid-19-patient-combat-the-condition-4079561/amp/

Please have a look at the attached document:

I dont think so.

Yes. In Ayurveda Immunity can be increased by taking only Arogyambu. Taking 4-liter water and reducing it to 1 liter is called Arogyambu in Ayurveda. Kindly find the attached screenshot of the Ayurveda reference. I am happy to share that  My wife Dr. Namrata Joshi is getting a significant result on Ashtadashang kadha in Patients with mild to moderate Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infections under AYUSH interventions related Research Studies on SARS-COV-2 Infection and COVID-19 disease under Extra Mural Research (EMR) Scheme.

Kadha described in different Ayurveda literature which may be helpful are

1. Dasamooladi kadha

2.Panchamoola kiratadi kadha

3. Dwadasanga pachana

4.Bruhatyadi kadha

5.Kantakaryadi kadha

6.Chaturdasanga kadha

7.Astadasanga kadha

8.Bhunimbadi- astadasanga kadha

9.Satyadi kadha

10.Mustaadi kadha

11.Vilwadi kadha

12.Vrihat katphaladi kadha

It requires more extensive research.

Please also have a look at the following attached article.

Please visit following link.

https://pubmed.ncbi.nlm.nih.gov/33251972/

Yes. Kadha(decoction) made from Tulsi (Basil), Dalchini (Cinnamon), Kalimirch (Black pepper), Shunthi (Dry Ginger) strengthens our immune system and has more of preventive effect.

However it's dosage & frequency of intake should be as per individual's body constitution.