FAQs on Cold Chain

Cold chain is a system for storing and transporting vaccines at recommended temperatures from point of manufacture till point of use (administration to beneficiary). The system comprises of walk-in freezers, walk-in coolers, deep freezers, ice-lined refrigerators installed at different levels for the storage of vaccines, and refrigerated vaccine vans/ insulated vaccine vans, vaccine carriers and insulated cold boxes for transportation. Entire system is closely monitored to ensure delivery of potent and effective vaccines to beneficiary.

At health facilities and immunization session sites, all vaccines should always be stored at the recommended temperature between +2OC to +8OC. Care should be taken to avoid keeping vaccines in conditions where the temperature is much lower (for example, freezers that are used for preparing ice), or where temperature is higher (for example, in direct sunlight). If a vaccine is not stored or transported at recommended temperature, there may be decline in potency and efficacy of the vaccine.

The order of different vaccines from bottom to top inside an ice lined refrigerator should be;

OPV (bottom most), Measles/MR, BCG, JE, Rotavirus, TT, DPT, IPV, Pentavalent, PCV, Hepatitis B, followed by diluents (top most).

Vaccine carrier   is   an   insulated   box used for transporting limited number of vaccine vials and diluents from cold chain point to outreach session sites, for storing vials at the session site, and to return back unused, partially used and completely used vials back to cold chain point on the same day. It is packed with four conditioned ice packs and can maintain storage temperature of +2OC to +8OC for 12 hours, if not opened frequently. Vaccine carriers are used globally for the purpose of transporting vaccines to the point of use. Note: Droppers and Syringes should not be kept in the vaccine carrier

At outreach immunization session sites (villages and mohallas); a health worker is responsible for maintaining appropriate cold chain for vaccines.

You should ensure that once the vaccines are transported to the session sites, the vaccine carrier is placed in shade and not in direct exposure to sunlight. During the session, avoid opening vaccine carrier frequently as this breaks the cold chain for vials stored inside. To address this, take out one conditioned ice pack outside the vaccine carrier and place non freeze-sensitive, opened vaccine vials on it, to maintain the recommended temperature.

As per guidelines, during an immunization session, take out one ice pack from vaccine carrier and place non freeze-sensitive, opened vaccine vials on it to maintain cold chain. This helps ensure that vaccine carrier is not opened again and again.

The vaccine vials that should be placed on ice pack are – BCG, Measles, OPV, Rotavirus and JE. BCG and Measles vials are placed in the pits provided on ice packs, while OPV, Rotavirus and JE are placed on the surface of ice pack.

The freeze-sensitive vaccine vials should NEVER be placed on ice pack. IPV, TT, DPT, PCV and Pentavalent vaccine vials should never be kept on the ice-pack.

Freeze sensitive vaccines (Hepatitis B, Pentavalent, IPV, DPT, TT and PCV) lose their potency if they freeze during storage or transportation. Therefore, if any of these vaccine vials are found visibly frozen, they should be discarded as per the guidelines.  A “shake test” should be performed at the health facility for any suspected frozen vaccine vial i.e. if temperature falls below 0°C or there are other frozen vials in the same box or there is any suspicious vial damaged due to freezing. Vaccines, like OPV and Rotavirus vaccines do not lose their potency and efficacy on freezing, and these vaccines can be used again once they liquefy.

Vaccine carrier should only be used for transporting vaccines and diluents provided under UIP to session sites. It should have four conditioned ice packs to ensure appropriate temperature inside carrier. No other vaccine (non UIP), drug, food, or item should be kept inside vaccine carrier. State-specific vaccines, if are part of the Routine Immunization may be transported in the same vaccine carrier. The droppers used for administration of oral vaccines and syringes should NOT be transported inside vaccine carrier as cold temperatures can cause them to crack.

Note: Hard frozen ice-packs should be used in vaccine carrier in case of Polio SIAs.

A vaccine diluent is the liquid which is used to reconstitute a lyophilized (freeze- dried) vaccine (BCG, Measles/MR and JE). A vaccine diluent may be sensitive to heat or freezing, and may require transportation and storage in the cold chain.

Yes. Diluents also should be stored in the ILR at the last cold chain point. If the ILR has space constraints then the diluents may be stored outside ILR, but it must be

  • ONLY the diluents supplied by the same manufacturer (bundled) along with vaccine are to be used as these are specifically designed for the needs of that vaccine, with respect to volume, pH level and chemical properties. No other diluents should be used even if they are chemically same.
  • Diluents should be checked for expiry date, batch numbers and breakage (cracks and leaks). Care should be taken to ensure that freeze dried vaccine (BCG, Measles/ MR and JE) are issued with corresponding diluents.
  • Only recommended volume of diluent must be used to reconstitute the vaccine. “Bundling” ensures vaccines are supplied with diluents, AD syringes and reconstitution syringes, in corresponding quantities, at each level of supply chain.

In VVM, the inner square (placed inside outer circle) changes colour gradually when exposed to high temperature. At the production facility, this square is white against the blue background of outer circle. As vial is exposed to heat at different points of time, the inner square begins to darken, and finally gets darker than colour of outer circle.

If the square is visible and lighter in colour, the vaccine is safe to use, though the vaccine in which the VVM is beginning to get dark should be used on priority. However, if the square is not visible or is darker in colour, the vaccine is NOT safe and should be discarded.


In all vaccines, VVM is present on the label; but in freeze-dried vaccines (viz. BCG, Measles, and JE) and Rotavirus Vaccine Vial, VVM is present on the cap. The reason for putting VVM on cap is that once these vials are opened for reconstitution, they should be used within 4 hours. For such vaccines, time after reconstitution is more important for ensuring efficacy and safety, and therefore should be discarded after 4 hours irrespective of their VVM status.

To address the avoidable wastage and ensure optimal utilization of life-saving vaccines, Ministry of Health & Family Welfare, Govt. of India, has adopted a Multi- Dose Open Vial Policy (OVP). The policy underlines guidelines for the reuse and storage of open vaccine vials of specific types that contain a few doses at the end of a session, provided certain criteria are fulfilled. Implementation of Open Vial Policy allows reuse of partially used multi dose vials of applicable vaccines under UIP in subsequent session (both fixed and outreach) up to four weeks (28 days) provided;

  • Expiry date has not passed
  • Vaccines are stored under appropriate cold chain conditions both during transportation and storage
  • Vaccine vial septum has not been submerged in water or contaminated in any way
  • Aseptic technique has been used to withdraw vaccine doses
  • VVM has not reached/crossed the discard point

Open Vial Policy is applicable on the open multi-dose vials of Hep B, OPV, IPV, PCV, DPT, TT and Pentavalent vaccine. The policy DOES NOT apply to freeze dried vaccines (BCG, Measles/MR and JE) and Rotavirus vaccines. These vaccines are to be used up to a maximum of 4 hours after opening.

As per the “Open Vial Policy” guidelines, 2015, all vaccine vials (partially used vials, empty vials and unopened vials) should be returned to the last cold chain point on the same day. At the cold chain point, the cold chain handler should ensure appropriate segregation as “To be used” and “Not to be used”, as per the following instructions; To be used

  • Unopened vials, if the VVM is intact and in usable stage
  • Partially used vials on which the open vial policy is applicable not to be used
  • Unopened vials, if the VVM is not in usable stage
  • Complete defacement of label of the vial
  • No mention of date/ time of opening on the opened vials
  • Open vials of BCG, Measles/ MR, JE and Rotavirus Vaccine
  • Empty vaccine vials

All returned vials (to be used and not be used) should be kept in the ILR. The vials marked as not to be used should be discarded after 48 hours or before the next session whichever is earlier. After this period, these vials should be discarded as per biomedical waste management protocol. This is done to ensure availability of vaccine vial for investigation, in case any adverse event occurs during this period. In case of any reported AEFI they will not be discarded but retained for further investigation.

If the date and time of opening is not mentioned on the opened vials, they should not be issued to any subsequent sessions. Such vaccine vials should be kept in the box “Not to be used” in ILR for 48 hours or before the next session, whichever is earlier and then must be discarded as per the guidelines.

eVIN is a Government of India’s initiative, launched in 2015, to support UIP by providing real-time information on vaccine stocks and flows, and storage temperature across all cold chain points of the country. In this system, cold chain handlers at all levels are provided with smart phones equipped with eVIN application for updating vaccine inventories. This is uploaded on a cloud server, which can then be viewed by programme managers at district, state and national level through online dashboards. In addition, system also helps to track storage temperature of vaccines through SIM- enabled temperature loggers, which record temperature data every ten minutes and update the server every hour via GPRS. In case of temperature breach, the logger alarms and sends email and SMS alerts to responsible cold chain technicians and managers.