The 10 Differences Between Rubella and Measles

Although both diseases present with a rash reaction, there are many differences between rubella and measles. Discover them with us.

Written and verified by el biólogo Samuel Antonio Sánchez Amador.

Last update: 10 July, 2023

There are several typical childhood illnesses that our parents had to go through at some point in their lives. These are not classified as serious, but the truth is that in previous times they caused notable associated morbidity and a burden on the health system. Although today there are vaccines that prevent them, its always interesting to know ábout these diseases, and today we’ll look at the differences between rubella and measles.

Although both are viral pathologies that cause itching and skin eruptions, rubella and measles are clearly distinguished in the symptomatic field, in their etiology, in transmissibility, and many other things. If you want to know everything about these diseases and how they manifest themselves in each patient, keep reading, as we show you the 10 differences between measles and rubella.

1. Each disease is caused by a different virus

To begin, we must emphasize that rubella and measles are closely related. It is only necessary to translate these terms into English to realize this, since rubella is known in English-speaking regions as German measles or three-day measles, while measles is called simply measles. Although similar words are used for them, they aren’t the same.

Rubella is an infectious virus caused by the rubella virus. This microorganism is found at the phylogenetic level in the Rubivirus genus and the Matonaviridae family, distinguishing itself from many other viruses by its single RNA chain surrounded by a protein membrane. Its genome is simple and contains 9762 nucleotides.

Measles is also an infectious virus, but its causative agent is very different. Although measles morbillivirus (MeV) is also a single-stranded RNA viral agent, it should be noted that it belongs to the genus Morbillivirus and to the family Paramyxoviridae. As you can see, it isn’t directly related to the cause of rubella.

Despite the differences in terms of taxonomy and genome, it should be noted that the pathogenic mechanism of viruses is similar in almost all cases. These biological agents lack cells (and therefore organelles), so they can’t replicate themselves autonomously. Thus, they enter the host’s cells and “hijack” its machinery to create copies of its RNA.

2. Different transmission mechanisms

To continue exploring the differences between rubella and measles, it’s necessary to introduce the term basic reproductive rhythm or R0. This concept is defined as ‘the average number of new cases generated by a given patient throughout an infectious period, that is, from when the pathogen is contracted until it is cured or dies’.

The method of estimating this value is complex, as it depends on the context (the country areas aren’t the same as the city), the incubation time, the symptomatic period, and the transmissibility of the microorganism itself. In any case, as a general rule, it’s expected that a pathogen with an R0 lower than 1 will end up disappearing over time, as it doesn’t spread quickly enough.

The basic reproductive rhythm or R0 for rubella is between 3.4 and 7.8, although it’s variable. This means that a person infected with the virus infects 5-7 people on average before healing. This value is very high, especially if we take into account that the R0 of much more common diseases (such as the flu) ranges between 1 and 3.

The basic reproductive rhythm of measles is much more striking, ranging between 12 and 18. This makes it one of the most infectious diseases in the world, surpassing even intestinal viruses that are transmitted very easily (R0 = 17). In other words, up to 9 out of 10 people who are exposed to an infected patient will become infected.

Rubella is transmitted by respiratory droplets, while measles is transmitted by air. Although it may seem anecdotal, this difference is vital; the droplets are larger and more easily deposited, while airway aerosols remain in suspension for longer.

3. Different epidemiological figures

Another of the central differences between rubella and measles lies in their epidemiological figures. As you can imagine, the disparity between the transmissibility of both pathologies greatly modulates their period of onset and their socioeconomic impact. We begin this section by saying that measles continues to be one of the leading causes of death that’s preventable with vaccination.

Before global vaccination, the infectious peak of rubella was between 5 and 9 years of age, as indicated. By way of an example, in high-income countries (such as Spain) the incidence has gone from 160,000 cases a year in the 1980s to less than 10 since 2012.

According to medical portals, the measles situation is similar. In the same country mentioned, its incidence has been reduced in recent years by 87%. This means that several decades ago there were about 145 cases per million inhabitants, while this figure today stands at 19. Deaths caused by the disease have also fallen by 84%.

Due to its greater danger and transmission rate , measles is monitored much more strictly than rubella. The ultimate goal is to end both diseases and immunize the entire population through vaccines, but measles is rather more serious at the epidemiological level and each outbreak is strictly monitored.

4. Rubella has a longer incubation time than measles

We have already explored the etiology, transmissibility, and epidemiology of both diseases. It’s now time to enter the symptomatic terrain, as the physiological parameters allow the two conditions to be differentiated with the naked eye. We start by exploring the incubation time.

As indicated by the Navarra University Clinic (CUN), the incubation time for rubella is 2 to 3 weeks. This means that the patient won’t begin to notice mild symptoms until 14-21 days after exposure to the pathogen. After this phase, the prodromal period begins, which we’ll look at later.

The incubation time for measles is considerably shorter, since the average from exposure to the pathogen to the first symptoms is 10-14 days. In other words, this phase can be extended to 1-2 weeks, but no longer. If the patient takes 21 days to show clear symptoms, it has to be rubella.

5. Different pathological mechanisms

Another of the baseline differences between rubella and measles lies in their pathophysiology. We’ll briefly explore what each virus does when it enters humans.

When rubella enters the host’s nasopharyngeal tissue, it infects susceptible cells through receptor-mediated endocytosis. Once integrated, the virus replicates in nasopharyngeal cells and spreads to lymphoid tissue in the throat and adjacent structures. After that, it enters the bloodstream (hematogenous route) and infects various organs 5-7 days after entering the host.

The pathophysiological mechanism of measles is similar, but presents certain disparities. It also enters the host through the nasopharyngeal tract, but in this case it invades the lymphocytes, macrophages, and dendritic cells of the alveolar tissue. After that, it expands to the adjacent lymphoid tissue and passes into the blood in order to infect various organs.

Although both mechanisms appear the same, there’s an essential distinction. Because measles initially infects lymphocytes, it causes some immunosuppression in the host. During a period of 4 to 6 weeks, patients infected with the measles virus are more susceptible to secondary infections, which isn’t the case in rubella.

6. The initial symptoms of measles are more noticeable

Once the incubation phase of both diseases passes, a mild prodromal or catarrhal stage begins. In both diseases, this period can be confused with flu, but measles is undoubtedly more serious at the symptomatic level. We present the characteristics of the initial phase of both conditions in the following list:

1. Rubella prodromal period: This appears with mild catarrhal symptoms, such as low-grade fever, swollen lymph nodes (at the base of the skull, the back of the neck, and behind the ears), a runny nose, and a headache. It lasts from 1 to 7 days.
2. Prodromal period of measles: As we have said, the symptoms in this condition are much more evident. High fever, malaise, catarrhal symptoms, irritating dry cough, runny nose, and a sore throat appear. It lasts about 4 days.

One of the clearest differences at the symptomatic level between rubella and measles in the prodromal phase is the intensity of the fever. In rubella the body temperature doesn’t rise above 38.9°C, while in measles it can reach 40°C. As you can imagine, this causes the patient to feel worse.

Another essential distinction on this front is swollen lymph nodes in the neck and head. With rubella, this symptom is always present in the initial phase after incubation, while in measles it isn’t a differential sign.

7. Koplik spots: presence or absence?

Another difference between rubella and measles is based on the presence or absence of Koplik’s spots. As indicated by the United States National Library of Medicine, these formations only occur with measles and consist of small white pimples that appear on the inner surface of the patient’s cheeks.

Koplik’s spots have a white center and are very small, but are well differentiated by the reddish contrast of the oral tissue. They appear just before the rash begins and don’t appear at any time with rubella. If the medical professional observes these superficial arises in the patient’s mouth, they will diagnose measles in all cases.

8. Skin rashes are different for each disease

After the prodromal phase, a rash period appears in both diseases, characterized by the appearance of lesions throughout the body. The type of rash is different in each of the pathologies that concern us here. We’ll explore them briefly in the following list:

• Rubella rash: These are non-confluent pink lesions characterized by the presence of macules and papules. It begins in the head and is distributed over the days to the rest of the body. Epidermal lesions are similar to measles (but less severe) and this phase usually lasts about 3 days.
• Measles rash: This is a red-wine rash that does converge. It appears first behind the ears and expands to the rest of the face, to later occupy the trunk and extremities, including the soles and palms. The fever in the prodromal phase worsens and a general malaise and sporadic anorexia are usually manifested. It lasts about 5 days.

Although it isn’t easy to distinguish between the two rashes if you aren’t a doctor, this difference can be summarized in that the measles rash is more severe and obvious. In addition, it’s usually accompanied by other more pronounced systemic clinical signs than in the case of rubella.

9. Different after effects

Rubella is considered a mild infection and its complications are few. In women, this disease is sometimes associated with arthritis in the fingers in adulthood, but it usually resolves on its own. It isn’t expected that serious side effects will appear after contracting the virus that causes rubella.

In contrast, complications after contracting the measles virus are relatively common. Among them, we highlight the following:

• Ear infection: As we have said, measles causes a temporary immunosuppression that favors the appearance of certain diseases. Otitis media occurs in up to 7% of patients.
• Bronchitis and pneumonia: Inflammation of the bronchial tubes and infection of the respiratory tract are also common in severe measles cases.
• Encephalitis: This appears in 1 in every 1000 patients. This term refers to an inflammation of the brain that can be fatal.

Due to the complications it causes, measles is considered a much more serious disease than rubella. An estimated 1 death per 1000 cases in measles patients, but the mortality rate can reach up to 10% in low-income countries where the disease is endemic.

10. Different treatment

Neither rubella nor measles have a definitive cure, since they’re viral diseases that only the patient’s own immune system can fight. However, there are certain differences between the conditions on this front.

Rubella doesn’t usually require any type of pharmacological approach, as it occurs with mild symptoms. In case the swelling of the lymph nodes is very bothersome, non-steroidal anti-inflammatory drugs (NSAIDs) can be prescribed. The same treatment is applied when rubella is accompanied by sporadic arthritic pictures in adults.

In measles, a supportive treatment is conceived, since the clinical signs are much more annoying and dangerous. The use of fever reducers (such as acetaminophen or ibuprofen) is usually necessary to reduce symptoms of high fever in the prodromal and exanthematic period. In addition, antibiotics are sometimes required to alleviate secondary infections resulting from the condition.

The importance of vaccination

We’ve introduced you to the key differences between measles and rubella this time, but we want to close with a slightly different message. Both diseases have reduced their incidence by more than 80% in high-income countries thanks to a process increasingly questioned in some sectors: vaccination.

There are 2 types of vaccines that protect children from measles and rubella equally (MMR and MMRV) that save thousands of lives each year. Thanks to the control of these diseases, it’s evident that vaccines are a necessary good for society and a necessity, especially to protect the most vulnerable people.