Lack of vaccine vial monitors (VVMs) on Covid vaccines has triggered concerns about their “effectiveness”. VVMs, according to the WHO, caution health workers if the vaccine is damaged due to overexposure to heat. However, neither Covishield nor Covaxin vials are provided with VVMs.
Vaccine scientist Gagandeep Kang said, “Covaxin and Covishield have both considered VVMs, and their submissions to the Drugs Controller General of India (DCGI) include presentations with and without monitors. A lot depends on what the purchaser wants.”
Interestingly, the issue was also discussed at the ongoing Legislative session. Congress MLC P R Ramesh had raised concerns over health workers’ inability to judge the effectiveness of the vaccine over prolonged use. “All vaccines, including polio vaccines, come with VVMs. But Covid vaccines don’t have them and the government must come clean on this,” Ramesh had demanded of the government.
Health and Medical Education Minister Dr Sudhakar had clarified that vaccines for polio and for Covid are different. “Both the vaccines are different and all vaccines cannot be treated the same way,” the minister had remarked.
A VVM is a circular label containing a square heat-sensitive material which is placed on a vaccine vial to register cumulative heat exposure over time. The inner square acquires a dark shade with exposure to heat.
Dr Rajeev Dheere, Executive Director, Serum Institute of India told DH that it is impossible to match the output of vaccine vials with a similar number of VVMs as there is so much demand for them. “If we require a specific VVM, then the raw material has to be imported in a significant quantity. The production of Covishield is massive compared to other vaccines. Covishield is beyond predictions. There is only one company that produces VVMs. We need to choose the VVM which then needs to be printed and pasted using the machines," he said.
An official said that in the absence of VVMs, the only option is to make sure the vaccine vials are used up within four hours of opening.
"If a VVM is there, the Covid vaccine vial could have been used for a longer time. Hence, now it is being discarded within four hours of opening. This is usually applicable to the last vial in the campaign as most of the vials get empty within an hour or so," explained the official requesting anonymity.