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CDL, Kasauli — the Himachal lab which makes sure that every Covid vaccine you get is safe

Central Drugs Laboratory, Kasauli, is only lab authorised to test safety & efficacy of vaccines in India, including those for Covid. It's also only lab authorised by WHO to test vaccines exported from India.

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Kasauli (Himachal Pradesh): A quaint, colonial-era laboratory, set in the mountains, has been at the centre of India’s Covid vaccination campaign, since it was launched earlier this year. The Central Drugs Laboratory (CDL) in Himachal Pradesh’s Kasauli is the only laboratory in India that has been authorised by the Government of India to check the safety and efficacy of vaccines, including the Covid vaccines, available in the Indian market.

It is also the only laboratory in the country that has been approved by the World Health Organization (WHO) to test the vaccines (Covid and non-Covid) that are being exported by India to 170 countries across the world.

When ThePrint visited the CDL campus on 15-16 June, the laboratory was testing 3.8 crore doses of Covishield and 70 lakh doses of Covaxin at its various testing rooms. Parallelly, the lab was also conducting its routine testing of other vaccines, such as those for polio, Bacille Calmette–Guérin (BCG, used against tuberculosis) and rotavirus.

According to the Ministry of Health and Family Welfare, India had administered 28 crore doses of Covid-19 vaccines by 20 June.

Since January — when Covid vaccines were launched in India — and until 14 June, the CDL has cleared more than 37 crore vaccine doses. These include 32 crore doses of Covishield, 3.94 crore doses of Covaxin and 1.5 lakh doses of Sputnik V.

For foreign-made vaccines that have been approved by established drug regulators such as the US Food & Drug Administration (FDA), the UK’s Medicines & Healthcare products Regulatory Agency (MHRA) or the WHO, the CDL reviews the necessary documents and approves their rollout in the market.

On an average, the laboratory releases around 7,000 batches of vaccines every year (in non-pandemic times) and has the capacity to test about 250 batches (number of doses in a batch may vary) in a month.

With the country set to accelerate its vaccination drive in the coming two months, the CDL is also expecting an increased workload, though lab officials did not specify by what percentage testing at the centre has increased in recent months.

What makes it even more challenging for them, however, is that the lab has to follow the Covid protocol of allowing only 50 per cent of staff to work on the campus on any given day.

“We have been told that this month will be crucial for all of us owing to the high inflow of consignments for testing,” an official at CDL said, adding that the lab is still trying to figure out how to follow the 50 per cent attendance norm in office, owing to the high work flow.

“We are planning to keep the ministerial (union health ministry employees, who coordinate between the CDL and the government) and administrative staff on work-from-home duty, whereas scientists and the technical staff will work from the offices in full strength,” the officer said, as he continued to work on clearing a dispatch of 50 lakh doses of Covishield.

Given the workload, the Narendra Modi government is on the lookout for other laboratories that can also test Covid vaccines, prior to their release in the market. The government is evaluating the National Centre for Cell Science (NCCS) in Pune for this. As of now, however, CDL is the only lab authorised to carry out these tests in India.

Also read: Bharat Biotech promised shot cheaper than bottled water. But Covaxin is 3rd costliest in world

‘No vaccine will hit the market unless approved by the CDL’

On 1 June, the Drugs Controller General of India (DCGI), in order to expedite the rollout of vaccines, decided to waive batch testing at CDL for foreign-manufactured vaccines that have been approved by international drug regulators such as the US FDA, the UK’s MHRA or the WHO.

However, despite the waiver, necessary documents of these vaccines, such as the summary lot protocol, which details the manufacturing procedures and tests carried out and the quality control processes followed, are to be first reviewed by the CDL before the vaccines are rolled out in the Indian market.

“No vaccines can be rolled out in the India market before receiving the approvals from CDL. Testing or no testing, the approval is in the hands of the CDL,” said the official quoted above.

He explained: “Sputnik V has not yet been approved by any top regulator, nor is it listed under WHO emergency use drugs. Hence, CDL will test all its batches before they are made available in the Indian market. In case the Pfizer vaccine is allowed to be sold in India, it has been approved by the US FDA and hence we will only review its documents and approve it for rollout in the market.”

Scientists at work in the lab | Himani Chandna | ThePrint
Scientists at work in the lab | Himani Chandna | ThePrint

The lab has recently expedited the approval process of Covid vaccines, by adopting a system of “parallel” testing, after facing severe pressure for delivering vaccines quickly into the market.

“Under parallel testing, the manufacturer sends some of its consignments to us as soon as it is out of their manufacturing process. While on one hand some of their consignments are being tested in their quality control room, the others are tested here at CDL. Eventually, we compare the test reports from both the labs (before approving its sale in the market). This saves about 14-15 days (in this system every dose of every batch is not tested at CDL),” the official said.

Also read: Why Novavax, a vaccine the world badly needs, is looking better than ever

Setting up the CDL and the testing process

Located on the campus of the Central Research Institute (CRI), Kasauli, CDL was once a part of the CRI.

Founded on 3 May 1905, the CRI, according to its website, was originally established with a mandate of research work in the field of medical and public health, manufacturing of vaccines and antisera, human resource development and to act as a national referral centre for public health problems.

The institute claims it is known for its contribution to vaccine production during the period of the World War 2, used for the immunisation of troops.

While CRI manufactured the vaccines, the CDL’s role was to test and approve these vaccines for market rollout. Due to the possible conflict of interest, CDL was separated from CRI in 2012 and was made into an independent organisation under the Ministry of Health and Family Welfare.

According to scientists at the CDL, the batch-testing of vaccines here involves multiple tests for checking the sterility, toxicity and efficacy of the dose, apart from conducting its basic biochemical testing.

“For Covid-19 vaccines, efficacy tests take two to three days. In this test, the vaccine’s efficacy is tested to match the claims published by the manufacturer on the product leaflet or product insert,” the official quoted above said.

Under efficacy testing, potency parameters of the vaccines are tested.

Safety tests are conducted on animals to check the toxicity of the dose, which takes around seven days.

Sterility tests, which check for the presence of any other micro-organism such as bacteria and fungi in the vaccine, take about two weeks. The test ensures the vaccine is “totally clean”.

The remaining tests are done in accordance with the “summary lot of protocol” of vaccine consignments, which mention the procedure of how the vaccine product is being manufactured and what tests are being carried out.

“We carry out those specific tests to verify their results,” said the official.

According to the official at CDL, the distance of the vaccine manufacturing sites, presently at Pune and Hyderabad (for Covishield and Covaxin, respectively) from the lab, does not cause any delay in the approval process.

“Serum Institute of India and Bharat Biotech (the manufacturers of Covishield and Covaxin, respectively) have been dealing with CDL for the past many decades. They have all logistics in place (for transportation of vaccine doses) and distance is not an issue,” he said.

(Edited by Poulomi Banerjee)

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