The Indian Council of Medical Research has invited expressions of interest from private companies to develop vaccines against monkeypox as the global threat from the viral disease deepens.
However, when the vaccine becomes available, it may be used only among high-risk individuals, who are yet to be clearly defined in the Indian context, according to officials in the government agency.
Some doctors have suggested that all those under 45 years who have not been vaccinated against smallpox as children (India stopped smallpox vaccinations in 1978) may need it if the disease becomes widespread. But scientists in the government and outside say that may not be necessary.
In a document issued on July 27, the ICMR said it is willing to make available monkeypox virus isolates for undertaking R&D, validation as well as manufacturing in the public-private partnership mode to develop vaccines and diagnostic kits for the viral disease.
The World Health Organization announced on July 28 that over 18,000 cases of the disease had been confirmed from 78 countries. The WHO declared monkeypox a public health emergency of international concern on July 23.
In India, four cases of the disease, mainly endemic in West and Central Africa prior to the latest outbreak, have been confirmed. One patient in New Delhi had no history of overseas travel, indicating the virus may be in community transmission in India.
Better to be prepared
However, most experts said this does not mean that everyone is at risk of contracting the disease, which is characterised by skin lesions and rashes in many cases.
“Our call for developing a monkeypox vaccine is only aimed at preparing in advance in case the disease emerges as a public health challenge in India,” a senior scientist associated with the ICMR clarified.
“It is always better to be prepared than to act late, when it comes to epidemics,” said clinician and medical researcher Rajeev Jayadevan.
Senior microbiologist and virologist Gagandeep Kang said a monkeypox vaccine makes sense for people who look after monkeypox patients, contacts of infected patients, and those at high risk.
“At the moment globally, these are men who have sex with men while other people do not need the vaccine,” she said.
Jayadevan, too, said the general population does not require to be vaccinated for monkeypox, only the most vulnerable.
“These include people with multiple sexual partners primarily. It is these networks that this virus is actively spreading in,” he said.
Jayadevan said that in addition to building focused awareness in these networks, ring vaccination will help reduce the spread of monkeypox. Ring vaccination is a strategy aimed at limiting the spread of a disease by administering vaccines to people in close contact with an infected person, such as family and friends.
Virologist JP Muliyil said that just as the rabies shot is not part of a universal vaccination programme but is available for those who are at high risk, having an option against monkeypox is much needed.
“What needs to be seen is whether the disease becomes endemic to India, which I think is unlikely,” he said.
Jayadevan pointed out that there will likely be a few spillover events of the disease into the general population and it will eventually die down, as it did during the US outbreak of 2003, where 39 people were confirmed to have monkeypox.
Four months into the current outbreak, almost 98 percent of the cases are from the MSM subgroup (men who have sex with men), especially those with multiple sexual partners, he said, adding that assertive interventions are needed in this subgroup.
“Rare and exceptional cases in children and women are expected from physical contact within families,” he said. “So far, these instances do not suggest rapid spread potential.”
Jayadevan said the virus may not spread widely in the general population for two reasons.
“First, in most monogamous individuals, the disease will come to a dead end within the family. When the person is feeling ill, it is unlikely that this person will actively spread the virus in the absence of such networks,” he said.
Secondly, unlike HIV or Hepatitis B, this virus does not cause long-term infection and the person stops becoming infectious as soon as the lesions heal, according to him.
‘Quick need of vaccine for those at highest risk’
Virologist Shahid Jameel, who is associated with the University of Oxford and Ashoka University, said while any preparation towards detection and protection is welcome, a vaccine, if needed, would be required before a new one could be developed, clinically tested and manufactured.
Considering India’s vaccine manufacturing capability, it would be best to have agreements to license the Bavarian Nordic and Japanese vaccines and produce them for low and middle-income countries.
Kang said among currently available monkeypox vaccines, Jynneos or Imvanex (Bavarian Nordic) is the safest, followed by ACAM2000 (Sanofi), a vaccine developed against smallpox.
Jynneos was developed because the smallpox vaccine had some serious side-effects – eczema vaccinatum, encephalitis and generalised vaccinia, which, while rare, could be debilitating, she said.
Jayadevan said these vaccines are based on the vaccinia virus and do not contain the smallpox or monkeypox virus. However, being live vaccines, they can cause side-effects, which, in rare cases, can be serious.
“For instance, 1 to 2 percent non-fatal cardiac effects are reported with these vaccines.
There are steps that can be taken to track the spread of monkeypox.
Jameel said the polymerase chain reaction (PCR) testing capabilities developed for Covid-19 can immediately be used for monkeypox.“Surveillance of this disease in sewage water is an attractive option, especially for large Indian cities, as it can be an early warning system and aid public health efforts,” he emphasised.