Monkeypox: What It Is and Which Vaccines Can Help

Last Updated:

3 min read

monkey on tree

Monkeypox is a rare disease normally found in tropical rainforests in Central and West Africa. It doesn't usually appear in non-endemic countries. However, as of May 21, WHO had received reports of 92 laboratory-confirmed cases of monkeypox and 28 suspected cases of monkeypox from 12 non-endemic Member States in Australia, Europe and North America.

What is monkeypox?

Monkeypox is a viral zoonosis (a virus transmitted from animals to humans) with symptoms very similar to those of smallpox, but clinically less severe. It is caused by the monkeypox virus which belongs to the orthopoxvirus genus of the Poxviridae family, the same family as those causing smallpox and cowpox. The name monkeypox comes from its initial discovery in laboratory monkeys in Denmark in 1958, while the first human case was recorded in 1970 in a child living in the Democratic Republic of the Congo. There are two clades of monkeypox virus: the milder West African clade — which accounts for all the recent cases – and the more severe Congo Basin (Central African) clade.

Signs and symptoms of monkeypox

Monkeypox symptoms in humans are similar to smallpox symptoms but less severe. The fundamental distinction between smallpox and monkeypox symptoms is that monkeypox causes swollen lymph nodes (lymphadenopathy), but smallpox does not. Monkeypox usually has a 7 to14 days incubation period (from infection to symptoms), but the range can vary from 5 to 21 days.

The sickness starts with:

  • Fever
  • Headache
  • Muscle aches
  • Backache
  • Swollen lymph nodes
  • Chills
  • Exhaustion

A rash appears 1 to 3 days (sometimes longer) following the occurrence of fever, often starting on the face and spreading to other parts of the body.


Lesions progress through the following stages before falling off:

  1. Macules
  2. Papules
  3. Vesicles
  4. Pustules
  5. Scabs

The disease usually lasts for 2-4 weeks. 


Content source: The US Centers for Disease Control and Prevention


Death rate

According to WHO, human infections with the West African clade appear to induce less severe disease than the Congo Basin clade, with a case fatality rate of 3.6% compared to 10.6% of the Congo Basin clade.

Monkeypox: methods of transmission

Despite the name “monkeypox”, it is rarely transmitted to humans by monkeys. More often, it is transmitted by rodents (including rats and squirrels) when they bite or scratch people, allowing the virus to enter the human body through broken skin. The virus may also enter through the respiratory tract or mucous membranes (eyes, nose or mouth). Animal-to-human transmission is also possible through bush meat preparation, direct or indirect contact (e.g. through contaminated bedding or clothing) with body fluids or lesion material.

Fortunately, monkeypox does not spread easily between people. Human-to-human transmission is thought to occur primarily through large respiratory droplets exchanged in prolonged face-to-face contact, as respiratory droplets generally cannot travel more than a few feet. Another method of transmission is direct or indirect contact (e.g. through contaminated bedding or clothing) with body fluids or lesion material.

Although monkeypox is not a sexually transmitted disease, close physical contact can facilitate infections. “Based on currently available information, cases have mainly but not exclusively been identified amongst men who have sex with men seeking care in primary care and sexual health clinics,” WHO reports.

Vaccines for monkeypox in Hong Kong

The existing vaccination against smallpox is at least 80% effective in protecting against the recent monkeypox infections, as Director of Health Dr. Ronald Lam Man-kin said in a government press conference. The Centre for Health Protection website states that there is currently no registered specific vaccine or antiviral pharmaceutical product for monkeypox available in Hong Kong. Nevertheless, Dr. Lam said the authorities are considering purchasing vaccines for protection against the disease.


Hong Kong has been providing free vaccinations against smallpox from the 1870s until the 1980s after the WHO announced the eradication of smallpox worldwide.


ACAM200 and JYNNEOSTM (also known as Imvamune or Imvanex) are the two licensed vaccines for smallpox in the United States and can be used to prevent monkeypox. 


Despite the precautionary measures, citizens in Hong Kong may not need to worry too much about monkeypox as monkeypox is not highly contagious and the risk of it being introduced into Hong Kong is relatively low, HKU microbiologist Dr. Ho Pak-Leung said.


Is monkeypox deadly?

The case fatality rate of human infections with the West African clade is 3.6% while that with the Congo Basin clade is 10.6%. 

What is the easiest-to-notice symptom of monkeypox?
Should Hong Kong citizens worry about monkeypox?
Healthy Matters

Unlock Premium Content For Free

Join the Healthy Club to get full access to all our exclusive content and special member discounts.

Already a member?

This article was independently written by Healthy Matters and is not sponsored. It is informative only and not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be relied upon for specific medical advice.

Share on