Multiple viruses have been linked to elevated blood pressure, and in some cases the evidence is strong enough to call the infection a genuine risk factor for developing hypertension. Cytomegalovirus, SARS-CoV-2, HIV, and hepatitis C have all been associated with higher blood pressure through overlapping but distinct biological pathways. The connection is not as straightforward as “you catch a virus and your blood pressure goes up the next day,” but the cumulative research, spanning animal experiments, large human cohort studies, and meta-analyses, makes clear that viral infections can contribute to hypertension in ways that persist long after the acute illness resolves.
Cytomegalovirus and the Earliest Evidence
Cytomegalovirus (CMV) is the virus with the longest track record in blood pressure research. Most people are infected at some point in life and carry the virus indefinitely, usually without symptoms. But a meta-analysis pooling data from multiple studies found a significant association between CMV infection and essential hypertension, the kind that develops without an obvious single cause and accounts for the vast majority of high blood pressure cases worldwide.1PubMed Central. Association of cytomegalovirus infection with hypertension risk: a meta-analysis Human population studies have backed this up in diverse groups. In a study of Kazakh and Han Chinese adults, CMV seropositivity and higher antibody levels were independently associated with hypertension even after adjusting for standard risk factors like age and weight.2PubMed Central. Human Cytomegalovirus Infection is Associated with Essential Hypertension in Kazakh and Han Chinese Populations
An important piece of the puzzle came from a mouse study that directly tested whether CMV could raise blood pressure on its own, without the confounding factors that plague human observational research. When mice were infected with CMV, their arterial blood pressure rose significantly, and this increase happened independently of atherosclerotic plaque in the aorta.3PLoS Pathogens. Cytomegalovirus Infection Causes an Increase of Arterial Blood Pressure That last detail matters because it suggests CMV does not need to clog arteries with plaque to push pressure up. The virus appears to affect blood vessels through other means.
How Viruses Push Blood Pressure Up
There is no single mechanism. Different viruses exploit different pathways, and some use more than one at once. But a few themes keep showing up.
Disrupting the Body’s Own Blood Pressure Regulator
Your body has a built-in system for controlling blood pressure called the renin-angiotensin system. One of the key molecules in this system, angiotensin II, constricts blood vessels and raises pressure. Another enzyme, ACE2, breaks down angiotensin II and generates a molecule that counteracts it, effectively acting as a brake on blood pressure. SARS-CoV-2 uses ACE2 as its entry point into cells. When the virus binds to ACE2 and pulls it inside the cell, less ACE2 is available on the cell surface to do its normal job.4PubMed Central. COVID-19, ACE2, and the cardiovascular consequences The result is that angiotensin II builds up while its counterbalancing molecule drops, shifting the balance toward higher blood pressure and more inflammation.5PubMed Central. Induced dysregulation of ACE2 by SARS-CoV-2 plays a key role in COVID-19 severity
Damaging the Blood Vessel Lining
The inner lining of blood vessels, the endothelium, produces nitric oxide to keep vessels relaxed and flexible. CMV has been shown to interfere with this process. In lab experiments, infected human endothelial cells produced more of a molecule called ADMA that blocks nitric oxide production, while also generating higher levels of damaging reactive oxygen species. The net effect is stiffer, less responsive blood vessels.6PubMed. Cytomegalovirus infection impairs the nitric oxide synthase pathway: role of asymmetric dimethylarginine in transplant arteriosclerosis Over time, this kind of endothelial damage contributes to the sustained vascular resistance that defines chronic hypertension.
Chronic Inflammation and Cytokine Overload
Viral infections trigger the immune system to release inflammatory signaling molecules called cytokines. In acute infections like severe COVID-19, this can escalate into a cytokine storm dominated by molecules like interleukin-6 and tumor necrosis factor-alpha.7PubMed Central. Interleukin-6 Perpetrator of the COVID-19 Cytokine Storm Even at lower levels, chronic viral infections keep the immune system in a state of persistent low-grade inflammation that damages blood vessels and stiffens arteries over months and years. This is a thread that ties together the hypertension seen with CMV, HIV, and hepatitis C: all three are chronic infections that keep prodding the immune system indefinitely.
COVID-19 and New-Onset Hypertension
The pandemic gave researchers an unprecedented opportunity to study what happens to blood pressure after a widespread viral infection. The findings have been surprisingly consistent. A systematic review and meta-analysis found that people who recovered from COVID-19 had a roughly 70% higher risk of developing new-onset hypertension within about seven months compared to uninfected controls, with about 13 out of every 1,000 COVID survivors developing hypertension versus about 8 out of every 1,000 control subjects over the same period.8PubMed Central. Risk of Incident New-Onset Arterial Hypertension After COVID-19 Recovery: A Systematic Review and Meta-analysis
Even nonsevere infections appeared to leave a mark. A study comparing people who had mild COVID-19 with matched controls found that diastolic blood pressure (the bottom number) was about 5 mmHg higher in the post-COVID group, and the odds of having blood pressure in the hypertensive range were roughly doubled.9PubMed Central. Increased blood pressure after nonsevere COVID-19 Five millimeters of mercury might not sound like much, but at a population level, a sustained shift of that size meaningfully increases cardiovascular risk.
When the Nervous System Gets Involved
Some of the blood pressure effects after COVID-19 appear to involve the autonomic nervous system, the part of the nervous system that controls heart rate, blood vessel tone, and blood pressure without you having to think about it. Researchers have found that a substantial fraction of people recovering from COVID-19 develop abnormal blood pressure responses when they stand up. In one study of hospitalized COVID patients evaluated after discharge, about a third showed exaggerated blood pressure rises upon standing, and these patients had roughly a sixfold to sevenfold increased risk of this abnormal response compared to healthy people who had not been infected.10PubMed Central. Exaggerated blood pressure elevation in response to orthostatic challenge, a post-acute sequelae of SARS-CoV-2 infection (PASC) after hospitalization
Another study found widespread autonomic dysfunction in post-COVID patients: about 86% had at least one abnormal cardiovascular reflex test, and they had higher rates of abnormal blood pressure drops upon standing as well.11PubMed Central. Post-Acute Effect of SARS-CoV-2 Infection on the Cardiac Autonomic Function The autonomic nervous system can malfunction in both directions after viral injury: some people experience pressure that shoots up too high when they stand, while others experience drops. Both patterns suggest the virus has disrupted the fine-tuned reflexes that normally keep blood pressure stable.
HIV, Hepatitis C, and Other Chronic Infections
The virus-hypertension connection extends well beyond CMV and COVID-19. People living with HIV face elevated hypertension risk through a combination of chronic inflammation from the virus itself, side effects of antiretroviral therapy, and downstream complications like kidney dysfunction and insulin resistance.12PubMed Central. HIV and hypertension epidemiology Disentangling which part of the risk comes from the virus and which comes from the medications is an ongoing challenge, but it is clear that the overall burden of hypertension is higher in this population than in the general public.
Hepatitis C offers a slightly different angle. A large multicenter study found that hypertension prevalence among hepatitis C patients was 39%, and crucially, the risk climbed in lockstep with liver damage. Patients with the most advanced scarring (stage F4 fibrosis) had hypertension rates approaching 48%, compared to 25% among those with only mild fibrosis.13PubMed Central. Hepatitis C Infection as a Risk Factor for Hypertension and Cardiovascular Diseases: An EpiTer Multicenter Study The liver is deeply involved in regulating fluid balance and producing proteins that affect blood vessels, so progressive liver disease from a chronic viral infection creates its own path toward higher blood pressure.
One of the most compelling pieces of evidence that the virus itself matters comes from treatment studies. When hepatitis C patients achieved a virologic response (meaning the virus was cleared from their blood) after antiviral treatment, their 24-hour average blood pressure dropped by about 15%.14International Journal of Advances in Medicine. Evolution of arterial hypertension in patients with hepatitis C virus cirrhosis after antiviral treatment If hypertension were purely a consequence of liver scarring, you would not expect clearing the virus to make such a quick difference. The fact that it does suggests the ongoing infection itself was actively contributing to the elevated pressure.
Viral Infections During Pregnancy
Pregnancy adds a layer of vulnerability. A systematic review of epidemiologic studies found that women with either a bacterial or viral infection during pregnancy had roughly twice the odds of developing preeclampsia, a dangerous condition defined by high blood pressure and organ damage.15PubMed. Association between maternal infections and preeclampsia: a systematic review of epidemiologic studies SARS-CoV-2 infection during pregnancy has been specifically linked to an increased risk of preeclampsia, with researchers identifying multiple pathways through which viruses can trigger the condition, including poor placenta development, stress on the outer layer of the placenta, and maternal systemic inflammation.16PubMed. Implication of viruses in the etiology of preeclampsia
A particularly striking finding involves autoantibodies. In pregnant women infected with SARS-CoV-2, researchers detected significantly elevated levels of autoantibodies that target the angiotensin II type 1 receptor, which plays a central role in blood pressure regulation. Women with both these autoantibodies and elevated levels of another protein marker were the ones who went on to develop chronic or gestational hypertension.17Med. SARS-CoV-2 infection induces the renin-angiotensin system in the placenta and is associated with pre-eclampsia This suggests the virus can trick the immune system into producing antibodies that directly activate blood pressure pathways, a mechanism distinct from the direct ACE2 disruption described earlier.
Children Are Not Spared
The assumption that children bounce back from viral infections without lasting cardiovascular effects has taken some hits. A study evaluating children at least eight weeks after a mild COVID-19 infection found that about 16% had elevated systolic blood pressure and about 11% met criteria for stage-1 hypertension, with their blood pressure readings significantly higher than those of healthy children who had not been infected.18PubMed. The Prevalence of Post-COVID-19 Hypertension in Children
Children who developed multisystem inflammatory syndrome (MIS-C) after COVID-19 fared worse. Even two years out, children who had experienced MIS-C had higher peripheral and central blood pressures than healthy controls.19Scientific Reports. Vascular and blood pressure alterations in children two years after multisystem inflammatory syndrome Whether these elevations persist into adolescence and adulthood remains unknown, but the fact that they were detectable two years later is not reassuring. Pediatricians have generally not been screening for post-infectious hypertension, and these findings suggest they should be paying closer attention.
What Happens to the Small Blood Vessels
Beyond the large arteries, viral infections can damage the smallest blood vessels, the capillaries, in ways that affect blood pressure. Researchers studying the skin capillaries of COVID-19 patients found microthomboses, tiny hemorrhages, and new vessel growth during the acute infection. Three months after discharge, those acute changes had resolved, but capillary density in the skin had dropped significantly, from roughly 97 capillaries per square millimeter during infection to about 76 three months later.20Europe PMC. Skin capillary alterations in patients with acute SarsCoV2 infection When the body loses small blood vessels, the remaining vessels must handle the same volume of blood through a smaller network, which increases resistance and raises pressure. This process, called microvascular rarefaction, is already recognized as both a cause and a consequence of hypertension. Viral infections may accelerate it.
CMV appears capable of a longer-term version of this damage. Researchers have proposed that CMV modifies smooth muscle cell function in artery walls, promotes chronic inflammation, and drives fibrosis of the arterial middle layer, all of which contribute to arterial stiffening and vascular aging.21PubMed Central. Arterial stiffness and vascular aging: mechanisms, prevention, and therapy – Section: Inflammation Stiffer arteries are less able to absorb the surge of blood with each heartbeat, which directly raises systolic blood pressure. This may help explain why CMV-positive people tend to have higher blood pressure even decades after their initial infection.
The Gut Virome Connection
One unexpected angle on viruses and blood pressure involves the viruses living in your gut. The gut is home to a massive community of bacteriophages (viruses that infect bacteria) and other viruses, collectively called the gut virome. A study comparing the gut viromes of people with hypertension, prehypertension, and normal blood pressure found that viral composition alone could distinguish hypertensive patients from healthy controls with about 90% accuracy.22Frontiers in Microbiology. The Human Gut Virome in Hypertension The viruses were not directly infecting the human host. Instead, they were likely reshaping the bacterial communities in the gut, which in turn affect metabolism, inflammation, and blood pressure through pathways that researchers are still mapping out. This is a young area of science, but it opens the possibility that viral communities you never feel or notice could be influencing your cardiovascular health in the background.
Can COVID-19 Vaccines Affect Blood Pressure?
Blood pressure spikes after COVID-19 vaccination have been reported, though the context matters. A meta-analysis covering more than 350,000 vaccinated individuals found that about 3% experienced some form of abnormal or increased blood pressure after vaccination, while the proportion experiencing severe hypertensive events was much smaller, roughly 0.6%.23PubMed Central. Blood Pressure Increase following COVID-19 Vaccination: A Systematic Overview and Meta-Analysis These increases were generally transient and self-limiting. The mechanism likely involves the short-lived inflammatory immune response that any vaccine is designed to provoke, not the sustained vascular damage caused by actual viral infection. For people already being treated for hypertension, the practical advice from most cardiology guidelines is to continue their medications and monitor their blood pressure around the time of vaccination, not to avoid it.
Kidneys as a Vulnerability Point
The kidneys regulate blood pressure by controlling how much fluid and salt the body retains. Several viruses can damage the kidneys directly or trigger immune-mediated kidney injury, and any significant kidney damage tends to push blood pressure up. HIV-associated kidney disease is a well-known pathway to hypertension in people living with HIV. For SARS-CoV-2, researchers have flagged that people with certain genetic variants (high-risk APOL1 alleles) are particularly susceptible to a type of kidney lesion called collapsing glomerulopathy after viral infection.24Circulation Research. Emerging Viral Infections and the Potential Impact on Hypertension, Cardiovascular Disease, and Kidney Disease These alleles are more common in people of recent African descent, which means viral infections may contribute to hypertension disparities that are already pronounced in this population. The kidney angle also helps explain why some people develop post-COVID hypertension while others with the same severity of infection do not: underlying genetic susceptibility and pre-existing kidney reserve likely make the difference.
Herpes Simplex and Arterial Cholesterol
Beyond the herpesviruses that grab headlines, herpes simplex virus type 1 (HSV-1, the common cold sore virus) has also been implicated in vascular changes. Laboratory research from the 1980s showed that HSV-1-infected arterial smooth muscle cells accumulated significantly more cholesterol esters and fats than uninfected cells, in part because the infection reduced the cells’ ability to break down stored cholesterol.25PubMed. Herpes simplex virus infection in human arterial cells. Implications in arteriosclerosis Infected cells also produced less prostacyclin, a molecule that normally helps keep arteries open and cholesterol metabolism humming. While this research focused on the arteriosclerosis angle rather than blood pressure directly, arterial walls loaded with fat and cholesterol are stiffer and less responsive, which feeds back into hypertension over time. Given that HSV-1 infects the majority of the global adult population and stays latent for life, even small effects on arterial health could matter at scale.